Anorexia Nervosa
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Anorexia nervosa (AN), often referred to simply as anorexia, is an
eating disorder An eating disorder is a mental disorder defined by abnormal eating behaviors that adversely affect a person's health, physical or mental health, mental health. These behaviors may include eating too much food or too little food. Types of eatin ...
characterized by food restriction,
body image disturbance Body image disturbance (BID) is a common symptom in patients with eating disorders and is characterized by an altered Body image, perception of one's own body. The onset is mainly attributed to patients with anorexia nervosa who persistently t ...
, fear of gaining weight, and an overpowering desire to be thin. Individuals with anorexia nervosa have a fear of being
overweight Being overweight is having more body fat than is optimally healthy. Being overweight is especially common where food supplies are plentiful and lifestyles are sedentary. , excess weight reached epidemic proportions globally, with more than ...
or being seen as such, despite the fact that they are typically
underweight An underweight person is a person whose body weight is considered too low to be healthy. A person who is underweight is malnourished. Assessment The body mass index, a ratio of a person's weight to their height, has traditionally been used t ...
. The
DSM-5 The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the '' Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiat ...
describes this perceptual symptom as "disturbance in the way in which one's body weight or shape is experienced". In
research Research is creative and systematic work undertaken to increase the stock of knowledge. It involves the collection, organization, and analysis of evidence to increase understanding of a topic, characterized by a particular attentiveness to ...
and clinical settings, this symptom is called "body image disturbance" or body dysmorphia. Individuals with anorexia nervosa also often deny that they have a problem with low weight due to their altered perception of appearance. They may weigh themselves frequently, eat small amounts, and only eat certain foods. Some patients with anorexia nervosa binge eat and
purge In history, religion and political science, a purge is a position removal or execution of people who are considered undesirable by those in power from a government, another, their team leaders, or society as a whole. A group undertaking such an ...
to influence their weight or shape. Purging can manifest as induced
vomit Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like food poisoning, gastroenteritis, pregna ...
ing, excessive exercise, and/or laxative abuse. Medical complications may include
osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...
,
infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...
, and heart damage, along with the cessation of menstrual periods. Complications in men may include lowered testosterone. In cases where the patients with anorexia nervosa continually refuse significant dietary intake and weight restoration interventions, a psychiatrist can declare the patient to lack capacity to make decisions. Then, these patients' medical proxies decide that the patient needs to be fed by restraint via nasogastric tube. Anorexia often develops during adolescence or young adulthood. One psychologist found multiple origins of anorexia nervosa in a typical female patient, but primarily sexual abuse and problematic familial relations, especially those of overprotecting parents showing excessive possessiveness over their children. The exacerbation of the mental illness is thought to follow a major life-change or stress-inducing events. Ultimately however, causes of anorexia are varied and differ from individual to individual. There is emerging evidence that there is a genetic component, with identical twins more often affected than fraternal twins. Cultural factors play a very significant role, with societies that value thinness having higher rates of the disease. Anorexia also commonly occurs in athletes who play sports where a low bodyweight is thought to be advantageous for aesthetics or performance, such as dance,
gymnastics Gymnastics is a group of sport that includes physical exercises requiring Balance (ability), balance, Strength training, strength, Flexibility (anatomy), flexibility, agility, Motor coordination, coordination, artistry and endurance. The movem ...
, running,
figure skating Figure skating is a sport in which individuals, pairs, or groups perform on figure skates on ice. It was the first winter sport to be included in the Olympic Games, with its introduction occurring at the Figure skating at the 1908 Summer Olympi ...
and
ski jumping Ski jumping is a winter sport in which competitors aim to achieve the farthest jump after sliding down on their skis from a specially designed curved ramp. Along with jump length, competitor's aerial style and other factors also affect the final ...
('' Anorexia athletica''). Treatment of anorexia involves restoring the patient back to a healthy weight, treating their underlying psychological problems, and addressing underlying maladaptive behaviors. A daily low dose of olanzapine has been shown to increase appetite and assist with weight gain in anorexia nervosa patients. Psychiatrists may prescribe their anorexia nervosa patients medications to better manage their
anxiety Anxiety is an emotion characterised by an unpleasant state of inner wikt:turmoil, turmoil and includes feelings of dread over Anticipation, anticipated events. Anxiety is different from fear in that fear is defined as the emotional response ...
or depression. Different therapy methods may be useful, such as
cognitive behavioral therapy Cognitive behavioral therapy (CBT) is a form of psychotherapy that aims to reduce symptoms of various mental health conditions, primarily depression, PTSD, and anxiety disorders. Cognitive behavioral therapy focuses on challenging and chang ...
or an approach where parents assume responsibility for feeding their child, known as
Maudsley family therapy Maudsley family therapy, also known as family-based treatment or Maudsley approach, is a family therapy for the treatment of anorexia nervosa devised by Christopher Dare and colleagues at the Maudsley Hospital in London. A comparison of family to ...
. Sometimes people require admission to a hospital to restore weight. Evidence for benefit from nasogastric tube feeding is unclear. Some people with anorexia will have a single episode and recover while others may have recurring episodes over years. The largest risk of
relapse In internal medicine, relapse or recidivism is a recurrence of a past (typically medical) condition. For example, multiple sclerosis and malaria often exhibit peaks of activity and sometimes very long periods of dormancy, followed by relapse or r ...
occurs within the first year post-discharge from eating disorder therapy treatment. Within the first two years post-discharge, approximately 31% of anorexia nervosa patients relapse. Many complications, both physical and psychological, improve or resolve with nutritional rehabilitation and adequate weight gain. It is estimated to occur in 0.3% to 4.3% of women and 0.2% to 1% of men in Western countries at some point in their life. About 0.4% of young women are affected in a given year and it is estimated to occur ten times more commonly among women than men. It is unclear whether the increased incidence of anorexia observed in the 20th and 21st centuries is due to an actual increase in its frequency or simply due to improved diagnostic capabilities. In 2013, it directly resulted in about 600 deaths globally, up from 400 deaths in 1990. Eating disorders also increase a person's risk of death from a wide range of other causes, including
suicide Suicide is the act of intentionally causing one's own death. Risk factors for suicide include mental disorders, physical disorders, and substance abuse. Some suicides are impulsive acts driven by stress (such as from financial or ac ...
. About 5% of people with anorexia die from complications over a ten-year period with medical complications and suicide being the primary and secondary causes of death respectively. Anorexia has one of the highest death rates among mental illnesses, second only to opioid overdoses.


Signs and symptoms

Anorexia nervosa is an eating disorder characterized by attempts to lose weight by way of
starvation Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism's life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, de ...
. A person with anorexia nervosa may exhibit a number of signs and symptoms, the type and severity of which may vary and be present but not readily apparent. Though anorexia is typically recognized by the physical manifestations of the illness, it is a mental disorder that can be present at any weight. Anorexia nervosa, and the associated
malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is a deficiency, excess, or imbalance of energy, protein and other nutrients which adversely affects the body's tissues a ...
that results from self-imposed starvation, can cause complications in every major
organ system An organ system is a biological system consisting of a group of organ (biology), organs that work together to perform one or more bodily functions. Each organ has a specialized role in an organism body, and is made up of distinct Tissue (biolog ...
in the body. Malnutrition can cause changes in the brain due to a lack of essential nutrients in the body.
Hypokalemia Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an a ...
, a drop in the level of potassium in the blood, is a sign of anorexia nervosa. A significant drop in potassium can cause abnormal heart rhythms,
constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The Human feces, stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the ...
, fatigue, muscle damage, and
paralysis Paralysis (: paralyses; also known as plegia) is a loss of Motor skill, motor function in one or more Skeletal muscle, muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory d ...
. Signs and symptoms may be classified in various categories including: physical, cognitive, affective, behavioral and perceptual:


Physical symptoms

* A low
body mass index Body mass index (BMI) is a value derived from the mass (Mass versus weight, weight) and height of a person. The BMI is defined as the human body weight, body mass divided by the square (algebra), square of the human height, body height, and is ...
for one's age and height (except in cases of atypical anorexia) * Rapid, continuous
weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...
* Dry hair and skin, hair thinning, as well as
hair loss Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarring ...
* Low body temperature (
hypothermia Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe ...
) * Raynaud Phenomenon *
Hypotension Hypotension, also known as low blood pressure, is a cardiovascular condition characterized by abnormally reduced blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood and is ...
or
orthostatic hypotension Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when they are standing up ( orthostasis) or sitting down. Primary orthostatic hypotension is also often referred to as ne ...
*
Bradycardia Bradycardia, also called bradyarrhythmia, is a resting heart rate under 60 beats per minute (BPM). While bradycardia can result from various pathological processes, it is commonly a physiological response to cardiovascular conditioning or due ...
or
tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...
* Chronic fatigue *
Insomnia Insomnia, also known as sleeplessness, is a sleep disorder where people have difficulty sleeping. They may have difficulty falling asleep, or staying asleep for as long as desired. Insomnia is typically followed by daytime sleepiness, low ene ...
* Having severe muscle tension, aches and pains * Irregular or absent menstrual periods * Infertility *
Gastrointestinal disease Gastrointestinal diseases (abbrev. GI diseases or GI illnesses) refer to diseases involving the Human gastrointestinal tract, gastrointestinal tract, namely the esophagus, stomach, small intestine, large intestine and rectum; and the accessory or ...
* Halitosis (from vomiting or starvation-induced
ketosis Ketosis is a metabolic state characterized by elevated levels of ketone bodies in the blood or urine. Physiological ketosis is a normal response to low glucose availability. In physiological ketosis, ketones in the blood are elevated above bas ...
) *
Abdominal distension Abdominal distension occurs when substances, such as air (gas) or fluid, accumulate in the abdomen causing its expansion. It is typically a symptom of an underlying disease or dysfunction in the body, rather than an illness in its own right. Peo ...
* Russell's Sign; can be a tell-tale sign of self-induced vomiting with scratches on the back of the hand * Tooth erosion *
Lanugo Lanugo is very thin, soft, usually unpigmented hair that is sometimes found on the body of a fetus or newborn. It is the first hair to be produced by the fetal hair follicles, and it usually appears around sixteen weeks of gestation and is abunda ...
: soft, fine hair growing over the face and body * Orange discoloration of the skin, particularly the feet (
Carotenosis Carotenosis is a benign and reversible medical condition where an excess of dietary carotenoids results in orange discoloration of the outermost skin layer. The discoloration is most easily observed in light-skinned people and may be mistaken fo ...
)


Cognitive symptoms

* An obsession with counting calories and monitoring contents of food * Preoccupation with food, recipes, or cooking; may cook elaborate dinners for others, but not eat the food themselves or consume a very small portion * Admiration of thinner people * Thoughts of being fat or not thin enough * An altered mental representation of one's body * Impaired
theory of mind In psychology and philosophy, theory of mind (often abbreviated to ToM) refers to the capacity to understand other individuals by ascribing mental states to them. A theory of mind includes the understanding that others' beliefs, desires, intent ...
, exacerbated by lower BMI and depression *
Memory impairment Amnesia is a deficit in memory caused by brain damage or brain diseases,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be temporarily caused by t ...
* Difficulty in abstract thinking and problem solving * Rigid and inflexible thinking * Poor
self-esteem Self-esteem is confidence in one's own worth, abilities, or morals. Self-esteem encompasses beliefs about oneself (for example, "I am loved", "I am worthy") as well as emotional states, such as triumph, despair, pride, and shame. Smith and Macki ...
* Hypercriticism and perfectionism


Affective symptoms

* Depression * Ashamed of oneself or one's body *
Anxiety disorders Anxiety disorders are a group of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal functions are significantly impaired. Anxiety may cause phys ...
* Rapid mood swings *
Emotional dysregulation Emotional dysregulation is characterized by an inability to flexibly respond to and manage emotional states, resulting in intense and prolonged emotional reactions that deviate from social norms, given the nature of the environmental stimuli enc ...
*
Alexithymia Alexithymia, also called emotional blindness, is a neuropsychological phenomenon characterized by significant challenges in recognizing, expressing, feeling, sourcing, and describing one's emotions. It is associated with difficulties in attachme ...


Behavioral symptoms

* Compulsive weighing * Regular body checking * Food restriction, both in terms of caloric content and type (for example, macronutrient groups) * Food rituals, such as cutting food into tiny pieces and measuring it, refusing to eat around others, and hiding or discarding of food * Purging, which may be achieved through self-induced vomiting,
laxatives Laxatives, purgatives, or aperients are substances that loosen human feces, stools and increase defecation, bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. ...
,
diet pills Anti-obesity medication or weight loss medications are pharmacological agents that reduce or control excess body fat. These medications alter one of the fundamental processes of the human anatomy, human body, body weight, weight regulation, by ...
,
emetics Vomiting (also known as emesis, puking and throwing up) is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Vomiting can be the result of ailments like Food-poisoning, food poisoning, gastroe ...
, diuretics, or exercise. The goals of purging are various, including the prevention of weight gain, discomfort with the physical sensation of being full or bloated, and feelings of guilt or impurity. * Excessive exercise or compulsive movement, such as pacing * Self harming or self-loathing * Social withdrawal and
solitude Solitude, also known as social withdrawal, is a state of seclusion or isolation, meaning lack of socialisation. Effects can be either positive or negative, depending on the situation. Short-term solitude is often valued as a time when one may wo ...
, stemming from the avoidance of friends, family, and events where food may be present * Excessive water consumption to create a false impression of
satiety Satiety ( /səˈtaɪ.ə.ti/ ''sə-TYE-ə-tee'') is a state or condition of fullness gratified beyond the point of satisfaction, the opposite of hunger. Following satiation (meal termination), satiety is a feeling of fullness lasting until the next ...
* Excessive
caffeine Caffeine is a central nervous system (CNS) stimulant of the methylxanthine chemical classification, class and is the most commonly consumed Psychoactive drug, psychoactive substance globally. It is mainly used for its eugeroic (wakefulness pr ...
consumption


Perceptual symptoms

* Unawareness or denial of severity of condition ( anosognosia), which may prevent some from seeking recovery * Perception of self as heavier or fatter than in reality, i.e.,
body image disturbance Body image disturbance (BID) is a common symptom in patients with eating disorders and is characterized by an altered Body image, perception of one's own body. The onset is mainly attributed to patients with anorexia nervosa who persistently t ...
* Altered body schema, i.e., a distorted and unconscious perception of one's body size and shape that influences how the individual experiences their body during physical activities. For example, a patient with anorexia nervosa may genuinely fear that they cannot fit through a narrow passageway. However, due to their malnourished state, their body is significantly smaller than someone with a normal BMI who would actually struggle to fit through the same space. In spite of having a small frame, the patient's altered body schema leads them to perceive their body as larger than it is.


Interoception

Interoception Interoception is the collection of Sense#Other internal sensations and perceptions, senses providing information to the organism about the internal state of the body. This can be both conscious and subconscious. It encompasses the brain's process ...
involves the conscious and unconscious sense of the internal state of the body, and it has an important role in
homeostasis In biology, homeostasis (British English, British also homoeostasis; ) is the state of steady internal physics, physical and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning fo ...
and regulation of emotions. Aside from noticeable physiological dysfunction, interoceptive deficits also prompt individuals with anorexia to concentrate on distorted perceptions of multiple elements of their body image. This exists in both people with anorexia and in healthy individuals due to impairment in interoceptive sensitivity and interoceptive awareness. Aside from weight gain and outer appearance, people with anorexia also report abnormal bodily functions such as indistinct feelings of fullness. This provides an example of miscommunication between internal signals of the body and the brain. Due to impaired interoceptive sensitivity, powerful cues of fullness may be detected prematurely in highly sensitive individuals, which can result in decreased calorie consumption and generate anxiety surrounding food intake in anorexia patients. People with anorexia also report difficulty identifying and describing their emotional feelings and the inability to distinguish emotions from bodily sensations in general, called
alexithymia Alexithymia, also called emotional blindness, is a neuropsychological phenomenon characterized by significant challenges in recognizing, expressing, feeling, sourcing, and describing one's emotions. It is associated with difficulties in attachme ...
. Interoceptive awareness and emotion are deeply intertwined, and could mutually impact each other in abnormalities. Anorexia patients also exhibit emotional regulation difficulties that ignite emotionally-cued eating behaviors, such as restricting food or excessive exercising. Impaired interoceptive sensitivity and interoceptive awareness can lead anorexia patients to adapt distorted interpretations of weight gain that are cued by physical sensations related to digestion (e.g., fullness). Combined, these interoceptive and emotional elements could together trigger maladaptive and negatively reinforced behavioral responses that assist in the maintenance of anorexia. In addition to metacognition, people with anorexia also have difficulty with social cognition including interpreting others' emotions, and demonstrating empathy. Abnormal interoceptive awareness and interoceptive sensitivity shown through all of these examples have been observed so frequently in anorexia that they have become key characteristics of the illness.


Comorbidity

Other psychological issues may factor into anorexia nervosa. Some pre-existing disorders can increase a person's likelihood to develop an eating disorder. Additionally, anorexia nervosa can contribute to the development of certain conditions. The presence of psychiatric comorbidity has been shown to affect the severity and type of anorexia nervosa symptoms in both adolescents and adults. Post traumatic stress disorder remains highly prevalent among patients with anorexia nervosa, with more comorbid PTSD being associated with more severe eating disorder symptoms. Obsessive-compulsive disorder (OCD) and obsessive-compulsive personality disorder (OCPD) are highly comorbid with AN. OCD is linked with more severe symptomatology and worse prognosis. The causality between personality disorders and eating disorders has yet to be fully established. Other comorbid conditions include depression,
alcoholism Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World He ...
,
substance abuse Substance misuse, also known as drug misuse or, in older vernacular, substance abuse, is the use of a drug in amounts or by methods that are harmful to the individual or others. It is a form of substance-related disorder, differing definition ...
, borderline and other
personality disorder Personality disorders (PD) are a class of mental health conditions characterized by enduring maladaptive patterns of behavior, cognition, and inner experience, exhibited across many contexts and deviating from those accepted by the culture. ...
s,
anxiety disorders Anxiety disorders are a group of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal functions are significantly impaired. Anxiety may cause phys ...
,
attention deficit hyperactivity disorder Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by symptoms of inattention, hyperactivity, impulsivity, and emotional dysregulation that are excessive and pervasive, impairing in multiple con ...
, and
body dysmorphic disorder Body dysmorphic disorder (BDD), also known in some contexts as dysmorphophobia, is a mental disorder defined by an overwhelming preoccupation with a perceived flaw in one's physical appearance. In BDD's delusional variant, the flaw is imagined ...
(BDD). Depression and anxiety are the most common comorbidities, and depression is associated with a worse outcome.
Autism spectrum Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing d ...
disorders occur more commonly among people with eating disorders than in the general population, with about 30% of children and adults with AN likely having autism. Zucker ''et al.'' (2007) proposed that conditions on the autism spectrum make up the cognitive endophenotype underlying anorexia nervosa and appealed for increased interdisciplinary collaboration.


Causes

There is evidence for biological, psychological, developmental, and sociocultural risk factors, but the exact cause of eating disorders is unknown.


Genetic

Anorexia nervosa is highly
heritable Heredity, also called inheritance or biological inheritance, is the passing on of Phenotypic trait, traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cell (biology), cells or orga ...
. Twin studies have shown a heritability rate of 28–58%. First-degree relatives of those with anorexia have roughly 12 times the risk of developing anorexia. Association studies have been performed, studying 128 different polymorphisms related to 43
genes In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
including genes involved in regulation of eating behavior,
motivation Motivation is an mental state, internal state that propels individuals to engage in goal-directed behavior. It is often understood as a force that explains why people or animals initiate, continue, or terminate a certain behavior at a particul ...
and reward mechanics,
personality traits In psychology, trait theory (also called dispositional theory) is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of ''traits'', which can be defined as habitual patterns of behavior, thou ...
and
emotion Emotions are physical and mental states brought on by neurophysiology, neurophysiological changes, variously associated with thoughts, feelings, behavior, behavioral responses, and a degree of pleasure or suffering, displeasure. There is ...
. Consistent associations have been identified for polymorphisms associated with agouti-related peptide, brain derived neurotrophic factor, catechol-o-methyl transferase, SK3 and opioid receptor delta-1. Epigenetic modifications, such as
DNA methylation DNA methylation is a biological process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter (genetics), promoter, DNA methylati ...
, may contribute to the development or maintenance of anorexia nervosa, though clinical research in this area is in its infancy. A 2019 study found a genetic relationship with mental disorders, such as
schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...
,
obsessive–compulsive disorder Obsessive–compulsive disorder (OCD) is a mental disorder in which an individual has intrusive thoughts (an ''obsession'') and feels the need to perform certain routines (''Compulsive behavior, compulsions'') repeatedly to relieve the dis ...
,
anxiety disorder Anxiety disorders are a group of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal functions are significantly impaired. Anxiety may cause phys ...
and depression; and metabolic functioning with a negative correlation with fat mass,
type 2 diabetes Type 2 diabetes (T2D), formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent ...
and
leptin Leptin (from Ancient Greek, Greek λεπτός ''leptos'', "thin" or "light" or "small"), also known as obese protein, is a protein hormone predominantly made by adipocytes (cells of adipose tissue). Its primary role is likely to regulate long ...
.


Environmental

Obstetric Obstetrics is the field of study concentrated on pregnancy, childbirth and the postpartum period. As a medical specialty, obstetrics is combined with gynecology under the discipline known as obstetrics and gynecology (OB/GYN), which is a surgic ...
complications: prenatal and perinatal complications may factor into the development of anorexia nervosa, such as
preterm birth Preterm birth, also known as premature birth, is the Childbirth, birth of a baby at fewer than 37 weeks Gestational age (obstetrics), gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 ...
, maternal
anemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...
,
diabetes mellitus Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...
, preeclampsia, placental infarction, and neonatal heart abnormalities. Neonatal complications may also have an influence on
harm avoidance Harm avoidance (HA) is a personality trait characterized by excessive worrying; pessimism; shyness; and being fearful, doubtful, and easily fatigued. In MRI studies HA was correlated with reduced grey matter volume in the orbito-frontal, occipita ...
, one of the
personality traits In psychology, trait theory (also called dispositional theory) is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of ''traits'', which can be defined as habitual patterns of behavior, thou ...
associated with the development of AN. Neuroendocrine dysregulation: altered signaling of peptides that facilitate communication between the gut, brain and
adipose tissue Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
, such as
ghrelin Ghrelin (; or lenomorelin, INN) is a hormone primarily produced by enteroendocrine cells of the gastrointestinal tract, especially the stomach, and is often called a "hunger hormone" because it increases the drive to eat. Blood levels of ghrel ...
,
leptin Leptin (from Ancient Greek, Greek λεπτός ''leptos'', "thin" or "light" or "small"), also known as obese protein, is a protein hormone predominantly made by adipocytes (cells of adipose tissue). Its primary role is likely to regulate long ...
,
neuropeptide Y Neuropeptide Y (NPY) is a 36 amino-acid neuropeptide that is involved in various physiological and homeostatic processes in both the central and peripheral nervous systems. It is secreted alongside other neurotransmitters such as GABA and glu ...
and
orexin Orexin (), also known as hypocretin, is a neuropeptide that regulates arousal, wakefulness, and appetite. It exists in the forms of orexin-A and orexin-B. The most common form of narcolepsy, type 1, in which the individual experiences brief loss ...
, may contribute to the pathogenesis of anorexia nervosa by disrupting regulation of hunger and satiety.
Gastrointestinal disease Gastrointestinal diseases (abbrev. GI diseases or GI illnesses) refer to diseases involving the Human gastrointestinal tract, gastrointestinal tract, namely the esophagus, stomach, small intestine, large intestine and rectum; and the accessory or ...
s: people with gastrointestinal disorders may be more at risk of developing disorders of eating practices than the general population, principally restrictive eating disturbances. An association of anorexia nervosa with
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
has been found. Individuals with good dietary management may develop anxiety, food aversion and eating disorders because of concerns around cross contamination of their foods. Some authors suggest that medical professionals should evaluate the presence of unrecognized celiac disease in all people with an eating disorder, especially if they present any gastrointestinal symptoms, (such as decreased appetite, abdominal pain, bloating, distension, vomiting, diarrhea or constipation), weight loss, or growth failure. With routinely asking celiac patients about weight or body shape concerns, dieting or vomiting for weight control, to evaluate the possible presence of an eating disorders, especially in women. Anorexia nervosa is more likely to occur in a person's pubertal years. Some explanatory hypotheses for the rising prevalence of eating disorders in adolescence are "increase of adipose tissue in girls, hormonal changes of puberty, societal expectations of increased independence and autonomy that are particularly difficult for anorexic adolescents to meet; ndincreased influence of the peer group and its values."


Anorexia as adaptation

Studies have hypothesized that disordered eating patterns may also arise secondary to starvation. The results of the Minnesota Starvation Experiment, for example, showed that normal controls will exhibit many of the same behavioral patterns associated with AN when subjected to starvation. Similarly, scientific experiments conducted using
mice A mouse (: mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
have suggested that other mammals exhibit these same behaviors, especially compulsive movement, when caloric restriction is induced, likely mediated by various changes in the neuroendocrine system. This has given further rise to the hypothesis that anorexia nervosa and other restrictive eating disorders may be an evolutionarily advantageous adaptive response to a perceived famine in the environment. Recent research has further expanded this perspective, showing how caloric restriction may be adaptive in volatile or uncertain environment - thus potentially explaining the association between an increased risk to develop anorexia nervosa and adverse childhood experiences.


Psychological

Early theories of the cause of anorexia linked it to childhood sexual abuse or dysfunctional families; evidence is conflicting, and well-designed research is needed. The fear of food is known as ''sitiophobia'' or ''cibophobia'', and is part of the differential diagnosis. Other psychological causes of anorexia include low self-esteem, feeling as if there is lack of control, depression,
anxiety Anxiety is an emotion characterised by an unpleasant state of inner wikt:turmoil, turmoil and includes feelings of dread over Anticipation, anticipated events. Anxiety is different from fear in that fear is defined as the emotional response ...
, and loneliness. People with anorexia are, in general, highly perfectionistic and most have obsessive compulsive personality traits which may facilitate sticking to a restricted diet. It has been suggested that patients with anorexia are rigid in their thought patterns, and place a high level of importance upon being thin. In the context of anorexia nervosa, this cognitive rigidity refers to the diminished ability to adapt one's behavioral approaches in response to changing circumstances. This weaker cognitive flexibility is a result of neurobiological factors, such as structural differences in prefrontal cortex connectivity, that contribute to the persistence of anorexic behaviors. Although the prevalence rates vary greatly, between 37% and 100%, there appears to be an association between traumatic events and eating disorder diagnosis. Approximately 72% of individuals with anorexia report experiencing a traumatic event prior to the onset of eating disorder symptoms, with binge-purge subtype reporting the highest rates. There are many traumatic events that have been identified as possible risk factors for the development of anorexia, the first of which was childhood sexual abuse. The prevalence of
post-traumatic stress disorder Post-traumatic stress disorder (PTSD) is a mental disorder that develops from experiencing a Psychological trauma, traumatic event, such as sexual assault, domestic violence, child abuse, warfare and its associated traumas, natural disaster ...
among anorexia nervosa patients ranges from 4% to 24%. A complicated symptom profile develops when trauma and anorexia meld; the bodily experience of the individual is changed and intrusive thoughts and sensations may be experienced. Traumatic events can lead to intrusive and obsessive thoughts, and the symptom of anorexia that has been most closely linked to a PTSD diagnosis is increased obsessive thoughts pertaining to food. Similarly, impulsivity is linked to the purge and binge-purge subtypes of anorexia, trauma, and PTSD. Emotional trauma (e.g., invalidation, chaotic family environment in childhood) may lead to difficulty with emotions, particularly the identification of and how physical sensations contribute to the emotional response. When trauma is perpetrated on an individual, it can lead to feelings of not being safe within their own body. Both physical and sexual abuse can lead to an individual seeing their body as belonging to an "other" and not to the "self". Individuals who feel as though they have no control over their bodies due to trauma may use food as a means of control because the choice to eat is an unmatched expression of control. By controlling the intake of food, individuals can decide when and how much they eat. Individuals, particularly children experiencing abuse, may feel a loss of control over their life, circumstances, and their own bodies. Particularly
sexual abuse Sexual abuse or sex abuse is abusive sexual behavior by one person upon another. It is often perpetrated using physical force, or by taking advantage of another. It often consists of a persistent pattern of sexual assaults. The offender is re ...
, but also
physical abuse Physical abuse is any intentional act causing injury or trauma to another person or animal by way of bodily contact. In most cases, children are the victims of physical abuse, but adults can also be victims, as in cases of domestic violence or ...
, can make individuals feel that the body is not a safe place and an object over which another has control.
Starvation Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism's life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, de ...
, in the case of anorexia, may also lead to reduction in the body as a sexual object, making starvation a solution. Restriction may also be a means by which the pain an individual is experiencing can be communicated.


Sociological

Anorexia nervosa has been increasingly diagnosed since 1950; the increase has been linked to vulnerability and internalization of body ideals. People in professions where there is a particular
social pressure Peer pressure is a direct or indirect influence on peers, i.e., members of social groups with similar interests and experiences, or social statuses. Members of a peer group are more likely to influence a person's beliefs, values, religion and beh ...
to be thin (such as models and dancers) were more likely to develop anorexia, and those with anorexia have much higher contact with cultural sources that promote weight loss. Internet usage heavily leads to deep societal practices of the upkeep of slender body types. Thus leading many to have symptoms of body dissatisfaction and low body image satisfaction. This trend can also be observed for people who partake in certain sports, such as jockeys and wrestlers. There is a higher incidence and prevalence of anorexia nervosa in sports with an emphasis on aesthetics, where low body fat is advantageous, and sports in which one has to make weight for competition. Family
group dynamics Group dynamics is a system of behaviors and psychological processes occurring within a social group (''intra''group dynamics), or between social groups ( ''inter''group dynamics). The study of group dynamics can be useful in understanding decision ...
can play a role in the perpetuation of anorexia including negative expressed emotion in overprotective families where blame is frequently experienced among its members. In the face of constant pressure to be thin, often perpetuated by teasing and bullying, feelings of low self-esteem and self-worth can arise, including the perception that one is not "deserving" of food.


Media effects

Persistent exposure to media that presents thin ideals may constitute a risk factor for body dysmorphia, leading to the development of anorexia nervosa. Western cultures that favor thin bodies as the beauty standard often have higher rates of anorexia nervosa. Media sources such as magazines, television shows, and social media can contribute to body dissatisfaction and disordered eating globally, by emphasizing slimness rooted in Western ideals. Among magazines popular with people aged 18 to 24, those with a predominantly male audience were more likely to feature advertisements and articles focused on body shape in relation to body culture rather than promoting healthy diet. In addition to the direct effect of media on female body perception, media indirectly affects female body image through giving men a false perception of what a female body is meant to look like. Body dissatisfaction and internalization of body ideals are risk factors for anorexia nervosa that threaten the health of both male and female populations, with a predominant focus on women. Another online aspect contributing to higher rates of eating disorders such as anorexia nervosa are websites and communities on social media that stress the importance attaining the "ideal" body. These communities promote anorexia nervosa through the use of religious metaphors, lifestyle demonstrations, and photo galleries or quotes meant to motivate the individual's pursuit of thinness (commonly referred to as "thinspiration," "bone-spiration," and "fitspiration"). These pro-anorexia websites reinforce internalization of body ideals and the importance of their attainment.


Cultural

Cultural attitudes towards body image, beauty, and health also significantly impact the incidence of anorexia nervosa. There is a stark contrast between Western societies that idolize slimness and certain Eastern traditions that worship gods depicted with larger bodies, and these varying cultural norms have varying influences on eating behaviors, self-perception, and anorexia in their respective cultures. For example, despite the fact that "fat phobia", or a fear of fat, is a key diagnostic criteria of anorexia by the DSM-5, anorexic patients in Asia rarely display this trait, as deep-rooted cultural values in Asian cultures praise larger bodies. Fat phobia appears to be intricately linked to Western culture, encompassing how various cultural perceptions impact anorexia in various ways. It calls on the need for greater, diverse cultural consideration when looking at the diagnosis and experience of anorexia. For instance, in a cross-sectional study done on British South Asian adolescent English adolescent anorexia patients, it was found that both patients' symptom profiles differed. South Asians were less likely to exhibit fat-phobia as a symptom versus their English counterparts, instead exhibiting loss of appetite. Patients usually attributed their restricted food intake to somatic symptoms such as bloating, stomach pain, or lack of appetite. However, both kinds of patients had distorted body images, implying the possibility of disordered eating and highlighting the need for cultural sensitivity when diagnosing anorexia. Collectivist and individualistic values also play a role in the manifestation of symptoms. Patients in
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
are more likely to display denial or minimization of symptoms since they are culturally encouraged to use conceal their symptoms to preserve group harmony. These cultural differences are further empathized in research on the Caribbean island of
Curaçao Curaçao, officially the Country of Curaçao, is a constituent island country within the Kingdom of the Netherlands, located in the southern Caribbean Sea (specifically the Dutch Caribbean region), about north of Venezuela. Curaçao includ ...
which revealed a substantially lower overall incidence of anorexia nervosa than that observed in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
and
Western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...
.  Specifically, no cases were identified among the majority
Black Black is a color that results from the absence or complete absorption of visible light. It is an achromatic color, without chroma, like white and grey. It is often used symbolically or figuratively to represent darkness.Eva Heller, ''P ...
population, while the minority mixed and
white White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...
population showed incidence rates similar to those in Western countries. This disparity highlights potential cultural variations in the development and presentation of anorexia nervosa, particularly when comparing Black women in Curaçao to those exposed to Western cultural influences. Notably, although these cultural distinctions persist, modernization and globalization slowly homogenize these attitudes. Anorexia is increasingly tied to the pressures of a global culture that celebrates Western ideals of thinness. The spread of Western media, fashion, and lifestyle ideals across the globe has begun to shift perceptions and standards of beauty in diverse cultures, contributing to a rise in the incidence of anorexia in places they were once rare. Anorexia, once primarily associated with Western culture, seems more than ever to be linked to the cultures of modernity and globalization. However, unique cultural-specific phenotypes of disordered eating emerged prior to Western influence. For example, restrictive eating patterns were found in
Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
as early as the 18th century and fewer reports of eating disorders were found between 1868 and 1944, when rapid Westernization occurred. Sex-specific stressors and cultural dynamics could be implicated in this independent development of anorexia nervosa symptomology.


Mechanisms

Evidence from physiological, pharmacological and neuroimaging studies suggest
serotonin Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, ...
(also called 5-HT) may play a role in anorexia. While acutely ill, metabolic changes may produce a number of biological findings in people with anorexia that are not necessarily causative of the anorexic behavior. For example, abnormal hormonal responses to challenges with serotonergic agents have been observed during acute illness, but not recovery. Nevertheless, increased
cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless Extracellular fluid#Transcellular fluid, transcellular body fluid found within the meninges, meningeal tissue that surrounds the vertebrate brain and spinal cord, and in the ventricular system, ven ...
concentrations of 5-hydroxyindoleacetic acid (a metabolite of serotonin), and changes in anorectic behavior in response to acute tryptophan depletion (
tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromat ...
is a metabolic precursor to serotonin) support a role in anorexia. The activity of the 5-HT2A receptors has been reported to be lower in patients with anorexia in a number of cortical regions, evidenced by lower binding potential of this receptor as measured by
PET A pet, or companion animal, is an animal kept primarily for a person's company or entertainment rather than as a working animal, livestock, or a laboratory animal. Popular pets are often considered to have attractive/ cute appearances, inte ...
or
SPECT Single-photon emission computed tomography (SPECT, or less commonly, SPET) is a nuclear medicine tomographic imaging technique using gamma rays. It is very similar to conventional nuclear medicine planar imaging using a gamma camera (that is, ...
, independent of the state of illness. While these findings may be confounded by comorbid psychiatric disorders, taken as a whole they indicate serotonin in anorexia. These alterations in serotonin have been linked to traits characteristic of anorexia such as obsessiveness, anxiety, and appetite dysregulation. Neuroimaging studies investigating the functional connectivity between brain regions have observed a number of alterations in networks related to cognitive control, introspection, and sensory function. Alterations in networks related to the dorsal anterior cingulate cortex may be related to excessive cognitive control of eating related behaviors. Similarly, altered somatosensory integration and introspection may relate to abnormal body image. A review of functional neuroimaging studies reported reduced activations in "bottom up" limbic region and increased activations in "top down" cortical regions which may play a role in restrictive eating. Compared to controls, people who have recovered from anorexia show reduced activation in the
reward system The reward system (the mesocorticolimbic circuit) is a group of neural structures responsible for incentive salience (i.e., "wanting"; desire or craving for a reward and motivation), associative learning (primarily positive reinforcement and c ...
in response to food, and reduced correlation between self reported liking of a sugary drink and activity in the
striatum The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamat ...
and
anterior cingulate cortex In human brains, the anterior cingulate cortex (ACC) is the frontal part of the cingulate cortex that resembles a "collar" surrounding the frontal part of the corpus callosum. It consists of Brodmann areas 24, 32, and 33. It is involved ...
. Increased binding potential of 11C radiolabelled
raclopride Raclopride is a typical antipsychotic. It acts as a selective antagonist on D2 dopamine receptors. It has been used in trials studying Parkinson Disease. Its selectivity to the cerebral D2 receptors is characterized by its respective Ki-va ...
in the striatum, interpreted as reflecting decreased endogenous
dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized ...
due to competitive displacement, has also been observed. Structural neuroimaging studies have found global reductions in both gray matter and white matter, as well as increased cerebrospinal fluid volumes. Regional decreases in the left
hypothalamus The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrin ...
, left inferior
parietal lobe The parietal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integra ...
, right
lentiform nucleus The lentiform nucleus (or lentiform complex, lenticular nucleus, or lenticular complex) are the putamen (laterally) and the globus pallidus (medially), collectively. Due to their proximity, these two structures were formerly considered one, howev ...
and right caudate have also been reported in acutely ill patients. However, these alterations seem to be associated with acute malnutrition and largely reversible with weight restoration, at least in nonchronic cases in younger people. In contrast, some studies have reported increased
orbitofrontal cortex The orbitofrontal cortex (OFC) is a prefrontal cortex region in the frontal lobes of the brain which is involved in the cognitive process of decision-making. In non-human primates it consists of the association cortex areas Brodmann area 11, 1 ...
volume in currently ill and in recovered patients, although findings are inconsistent. Reduced
white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...
integrity in the fornix has also been reported.


Diagnosis

A diagnostic assessment includes the person's current circumstances, biographical history, current symptoms, and family history. The assessment also includes a mental state examination, which is an assessment of the person's current mood and thought content, focusing on views on weight and patterns of eating.


DSM-5

Anorexia nervosa is classified under the Feeding and Eating Disorders in the latest revision of the ''
Diagnostic and Statistical Manual of Mental Disorders The ''Diagnostic and Statistical Manual of Mental Disorders'' (''DSM''; latest edition: ''DSM-5-TR'', published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a com ...
'' (DSM 5). There is no specific BMI cut-off that defines low weight required for the diagnosis of anorexia nervosa. The diagnostic criteria for anorexia nervosa (all of which needing to be met for diagnosis) are: * Restriction of energy intake relative to requirements leading to a low body weight. (Criterion A) * Intense fear of gaining weight or persistent behaviors that interfere with gaining weight. (Criterion B) * Disturbance in the way a person's weight or body shape is experienced or a lack of recognition about the risks of the low body weight. (Criterion C) Relative to the previous version of the DSM (
DSM-IV-TR The ''Diagnostic and Statistical Manual of Mental Disorders'' (''DSM''; latest edition: ''DSM-5-TR'', published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a c ...
), the 2013 revision (DSM5) reflects changes in the criteria for anorexia nervosa. Most notably, the amenorrhea (absent period) criterion was removed. Amenorrhea was removed for several reasons: it does not apply to males, it is not applicable for females before the age of menstruation, during or after the menopause, or women of any age taking birth control. Additionally, some women who meet the other criteria for AN still report some menstrual activity.


Subtypes

There are two subtypes of AN: * Restrictive Type: In the most recent months leading up to the evaluation, the patient has not engaged in binging and purging via laxative or diuretic abuse, enemas, or self-induced vomiting. The weight loss accomplished in this patient is mainly through the use of one or more of the following methods: fasting, dieting, and excessive exercise. * Binge-eating / Purging Type: In the last few months, the patient has recurrently engaged in binge-purge cycles.


Levels of severity

The use of the
body mass index Body mass index (BMI) is a value derived from the mass (Mass versus weight, weight) and height of a person. The BMI is defined as the human body weight, body mass divided by the square (algebra), square of the human height, body height, and is ...
in the diagnosis of eating disorders has been controversial, largely owing to its oversimplification of health and failure to take into account complicating factors such as body composition or the initial bodyweight of the patient prior to the onset of AN. As such, the DSM-5 does not have a strict BMI cutoff for the diagnosis of anorexia nervosa, but it nevertheless uses BMI to establish levels of severity, which it states as follows: * Mild: BMI of greater than 17 * Moderate: BMI of 16–16.99 * Severe: BMI of 15–15.99 * Extreme: BMI of less than 15


Investigations

Medical tests to check for signs of physical deterioration in anorexia nervosa may be performed by a general physician or psychiatrist. Physical examination: * Blinded weight: The patient will strip and put on a surgical gown alone. The patient will step backwards onto the scale as the healthcare provider blocks the reading from the patient's line of vision. * Orthostatic vitals: The patient lies completely flat for five minutes, and then, the medical provider measures the patient's blood pressure and heart rate. The patient stands up and stays stationary for two minutes. Then, the blood pressure and heart rate are assessed again, making note of any patient symptoms upon standing like dizziness. According to the College of Family Physicians of Canada, a change in orthostatic heart rate greater than 20 beats/minute or a change in orthostatic blood pressure greater than 10mmHg can warrant admission for an adolescent. * Examination of hands and arms for brittle nails, Russell's sign, swollen joints,
lanugo Lanugo is very thin, soft, usually unpigmented hair that is sometimes found on the body of a fetus or newborn. It is the first hair to be produced by the fetal hair follicles, and it usually appears around sixteen weeks of gestation and is abunda ...
, and self harm. * Auscultation of the chest for rubs, gallops, thrills, murmurs, and apex beat. * Examination of the face for puffiness, dental decay, swollen parotid glands, and conjunctival hemorrhage. Blood tests: *
Complete blood count A complete blood count (CBC), also known as a full blood count (FBC) or full haemogram (FHG), is a set of medical laboratory tests that provide cytometry, information about the cells in a person's blood. The CBC indicates the counts of white blo ...
(CBC): a test of the
white blood cells White blood cells (scientific name leukocytes), also called immune cells or immunocytes, are cells of the immune system that are involved in protecting the body against both infectious disease and foreign entities. White blood cells are genera ...
,
red blood cells Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...
and
platelets Platelets or thrombocytes () are a part of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping to form a blood clot. Platelets have no cell nucleus; they are fragments of cyto ...
used to assess the presence of various disorders such as leukocytosis,
leukopenia Leukopenia () is a decrease in the number of white blood cells (leukocytes). It places individuals at increased risk of infection as white blood cells are the body's primary defense against infections. Signs and symptoms Symptoms may include: * s ...
, thrombocytosis and
anemia Anemia (also spelt anaemia in British English) is a blood disorder in which the blood has a reduced ability to carry oxygen. This can be due to a lower than normal number of red blood cells, a reduction in the amount of hemoglobin availabl ...
which may result from
malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is a deficiency, excess, or imbalance of energy, protein and other nutrients which adversely affects the body's tissues a ...
. * Chem-20: Chem-20, also known as SMA-20, is a group of twenty separate chemical tests performed on blood serum. Tests include
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
and
electrolytes An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble salts, acids, and bases, dissolved in a polar solvent like water. Upon dissolving, t ...
such as
potassium Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to ...
,
chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...
and
sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
, and tests specific to
liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...
and
kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...
function. * Glucose tolerance test: Oral glucose tolerance test (OGTT) used to assess the body's ability to metabolize glucose. Can be useful in detecting various disorders such as
diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...
, an insulinoma, Cushing's Syndrome,
hypoglycemia Hypoglycemia (American English), also spelled hypoglycaemia or hypoglycæmia (British English), sometimes called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's tria ...
and
polycystic ovary syndrome Polycystic ovary syndrome, or polycystic ovarian syndrome, (PCOS) is the most common endocrine disorder in women of reproductive age. The name is a misnomer, as not all women with this condition develop cysts on their ovaries. The name origin ...
. *
Lipid profile A lipid profile or lipid panel is a Test panel, panel of blood tests used to find abnormalities in blood lipid ( such as cholesterol and triglycerides) concentrations. The results of this test can identify certain Inborn error of lipid metabolis ...
: includes
cholesterol Cholesterol is the principal sterol of all higher animals, distributed in body Tissue (biology), tissues, especially the brain and spinal cord, and in Animal fat, animal fats and oils. Cholesterol is biosynthesis, biosynthesized by all anima ...
(including total cholesterol, HDL and LDL) and
triglycerides A triglyceride (from ''wikt:tri-#Prefix, tri-'' and ''glyceride''; also TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids. Triglycerides are the main constituents of body fat in humans and oth ...
. * Serum
cholinesterase The enzyme cholinesterase (EC 3.1.1.8, choline esterase; systematic name acylcholine acylhydrolase) catalyses the hydrolysis of choline-based esters: : an acylcholine + H2O = choline + a carboxylate Several of these serve as neurotransmitte ...
test: a test of liver enzymes (
acetylcholinesterase Acetylcholinesterase (HUGO Gene Nomenclature Committee, HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme th ...
and pseudocholinesterase) useful as a test of liver function and to assess the effects of malnutrition. * Liver function tests: A series of tests used to assess liver function some of the tests are also used in the assessment of malnutrition, protein deficiency, kidney function, bleeding disorders, and Crohn's Disease. *
Luteinizing hormone Luteinizing hormone (LH, also known as luteinising hormone, lutropin and sometimes lutrophin) is a hormone produced by gonadotropic cells in the anterior pituitary gland. The production of LH is regulated by gonadotropin-releasing hormone (G ...
(LH) response to
gonadotropin-releasing hormone Gonadotropin-releasing hormone (GnRH) is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is a tropic peptide hormone synthesized and rele ...
(GnRH): Tests the pituitary glands' response to GnRh, a hormone produced in the hypothalamus.
Hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...
is often seen in anorexia nervosa cases. *
Creatine kinase Creatine kinase (CK), also known as creatine phosphokinase (CPK) or phosphocreatine kinase, is an enzyme () expressed by various tissues and cell types. CK catalyses the conversion of creatine and uses adenosine triphosphate (ATP) to create phos ...
(CK) test: measures the circulating blood levels of creatine kinase an enzyme found in the heart (
CK-MB The CPK-MB test (creatine phosphokinase-MB), also known as CK-MB test, is a cardiac marker used to assist diagnoses of an acute myocardial infarction, myocardial ischemia, or myocarditis. It measures the blood level of CK-MB (creatine kinase my ...
), brain (CK-BB) and skeletal muscle (CK-MM). * Blood urea nitrogen (BUN) test: urea nitrogen is the byproduct of protein metabolism first formed in the liver then removed from the body by the kidneys. The BUN test is primarily used to test
kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...
function. A low BUN level may indicate the effects of malnutrition. *
BUN-to-creatinine ratio In medicine, the urea-to-creatinine ratio (UCR), known in the United States as BUN-to-creatinine ratio, is the ratio of the blood levels of urea ( BUN) (mmol/L) and creatinine (Cr) (μmol/L). BUN only reflects the nitrogen content of urea (MW 28) ...
: A BUN to creatinine ratio is used to predict various conditions. A high BUN/creatinine ratio can occur in severe hydration, acute kidney failure, congestive heart failure, and intestinal bleeding. A low BUN/creatinine ratio can indicate a low protein diet,
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...
, rhabdomyolysis, or
cirrhosis Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, chronic liver failure or chronic hepatic failure and end-stage liver disease, is a chronic condition of the liver in which the normal functioning tissue, or parenchyma, is replaced ...
of the liver. *
Thyroid function tests Thyroid function tests (TFTs) is a collective term for blood tests used to check the function of the thyroid. TFTs may be requested if a patient is thought to suffer from hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid) ...
: tests used to assess thyroid functioning by checking levels of thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3). Additional medical screenings: *
Urinalysis Urinalysis, a portmanteau of the words ''urine'' and ''analysis'', is a Test panel, panel of medical tests that includes physical (macroscopic) examination of the urine, chemical evaluation using urine test strips, and #Microscopic examination, m ...
: a variety of tests performed on the urine used in the diagnosis of medical disorders, to test for substance abuse, and as an indicator of overall health * Electrocardiogram (EKG or ECG): measures electrical activity of the heart. It can be used to detect various disorders such as
hyperkalemia Hyperkalemia is an elevated level of potassium (K+) in the blood. Normal potassium levels are between 3.5 and 5.0 mmol/L (3.5 and 5.0 mEq/L) with levels above 5.5mmol/L defined as hyperkalemia. Typically hyperkalemia does not cause symptoms. Oc ...
. *
Electroencephalogram Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The bio signals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neoc ...
(EEG): measures the electrical activity of the brain. It can be used to detect abnormalities such as those associated with pituitary tumors.


Differential diagnoses

A variety of medical and psychological conditions have been misdiagnosed as anorexia nervosa; in some cases the correct diagnosis was not made for more than ten years. The distinction between binge purging anorexia,
bulimia nervosa Bulimia nervosa, also known simply as bulimia, is an eating disorder characterized by binge eating (eating large quantities of food in a short period of time, often feeling out of control) followed by compensatory behaviors, such as self-indu ...
and Other Specified Feeding or Eating Disorders (OSFED) is often difficult for non-specialist clinicians. A main factor differentiating binge-purge anorexia from bulimia is the gap in physical weight. Patients with bulimia nervosa are ordinarily at a healthy weight, or slightly overweight. Patients with binge-purge anorexia are commonly underweight. Moreover, patients with the binge-purging subtype may be significantly underweight and typically do not binge-eat large amounts of food. In contrast, those with bulimia nervosa tend to binge large amounts of food. It is not unusual for patients with an eating disorder to "move through" various diagnoses as their behavior and beliefs change over time.


Treatment

Treatment for people with anorexia nervosa should be individualized and tailored to each person's medical, psychological, and nutritional circumstances. Treating this condition with an interdisciplinary team is suggested so that the different health care professional specialties can help addresses the different challenges that can be associated with recovery. Treatment for anorexia typically involves a combination of medical, psychological interventions such as therapy, and nutritional interventions (diet) interventions. Hospitalization may also be needed in some cases, and the person requires a comprehensive medical assessment to help direct the treatment options. There is no conclusive evidence that any particular treatment approach for anorexia nervosa works better than others. In some clinical settings a specific body image intervention is performed to reduce body dissatisfaction and
body image disturbance Body image disturbance (BID) is a common symptom in patients with eating disorders and is characterized by an altered Body image, perception of one's own body. The onset is mainly attributed to patients with anorexia nervosa who persistently t ...
. Although restoring the person's weight is the primary task at hand, optimal treatment also includes and monitors behavioral change in the individual as well. In general, treatment for anorexia nervosa aims to address three main areas: * Restoring the person to a healthy weight; * Treating the psychological disorders related to the illness; * Reducing or eliminating behaviors or thoughts that originally led to the disordered eating.


Psychological support

Psychological support, often in the form of cognitive-behavioral therapy (CBT), family-based treatment, or psychotherapy aims to change distorted thoughts and behaviors around food, body image, and self-worth, with family-based therapy also being a key approach for younger patients.


Family-based therapy

Family-based treatment (FBT) may be more successful than individual therapy for adolescents with AN. Various forms of family-based treatment have been proven to work in the treatment of adolescent AN including conjoint family therapy (CFT), in which the parents and child are seen together by the same therapist, and separated family therapy (SFT) in which the parents and child attend therapy separately with different therapists. Proponents of family therapy for adolescents with AN assert that it is important to include parents in the adolescent's treatment. The evidence supporting family based therapy for adults is weak and despite the evidence that it is effective and the primary choice for treatment in adolescents, there is no evidence it is helpful for adults. A four- to five-year follow up study of the
Maudsley family therapy Maudsley family therapy, also known as family-based treatment or Maudsley approach, is a family therapy for the treatment of anorexia nervosa devised by Christopher Dare and colleagues at the Maudsley Hospital in London. A comparison of family to ...
, an evidence-based manualized model, showed full recovery at rates up to 90%. The Maudsley model of family therapy is problem focused, and the treatment targets re-establishing regular eating, weight restoration, and the reduction of illness behaviors like purging. The Maudsley model is split into three phases, with phase one focusing on the parents implementing weight restoration in the child; phase two transitioning control over food back to the individual at an age-appropriate level; and phase three focusing on other issues related to typical adolescent development (e.g., social and other psychological developments), and helps parents learn how to interact with their child. Although this model is recommended by the National Institute of Mental Health ( NIMH), critics claim that it has the potential to create power struggles in an intimate relationship and may disrupt equal partnerships.


Cognitive behavioral therapy

Cognitive behavioral therapy Cognitive behavioral therapy (CBT) is a form of psychotherapy that aims to reduce symptoms of various mental health conditions, primarily depression, PTSD, and anxiety disorders. Cognitive behavioral therapy focuses on challenging and chang ...
(CBT) is useful in adolescents and adults with anorexia nervosa. One of the most known psychotherapy in the field is CBT-E, an enhanced cognitive-behavior therapy specifically focus to eating disorder psychopathology.
Acceptance and commitment therapy Acceptance and commitment therapy (ACT, typically pronounced as the word "act") is a form of psychotherapy, as well as a branch of clinical behavior analysis. It is an empirically-based psychological intervention that uses acceptance and mindfu ...
is a third-wave cognitive-behavioral therapy which has shown promise in the treatment of AN. Cognitive remediation therapy (CRT) is also used in treating anorexia nervosa. Schema-Focused Therapy (a form of CBT) was developed by Dr. Jeffrey Young and is effective in helping patients identify origins and triggers for disordered eating.


Psychotherapy

Psychotherapy Psychotherapy (also psychological therapy, talk therapy, or talking therapy) is the use of Psychology, psychological methods, particularly when based on regular Conversation, personal interaction, to help a person change behavior, increase hap ...
for individuals with AN is challenging as they may value being thin and may seek to maintain control and resist change. Initially, developing a desire to change is fundamental. There is no strong evidence to suggest one type of psychotherapy over another for treating anorexia nervosa in adults or adolescents.


Diet

Diet is the most essential factor to work on in people with anorexia nervosa, and must be tailored to each person's needs. Food variety is important when establishing meal plans as well as foods that are higher in energy density, especially in
carbohydrates A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ma ...
and dietary fat, which are easier for the undernourished body to break down. Evidence of a role for zinc supplementation during refeeding is unclear. Dieticians work with the medical team to add dietary supplements like iron, every other day, or calcium. Historically, practitioners have slowly increased calories at a measured pace from a starting point of around 1,200 kcal/day. However, as understanding of the process of weight restoration has improved, an approach that favors a higher starting point and a more rapid rate of increase has become increasingly common. In either approach, the end goal is typically in the range of 3,000 to 3,500 kcal/day.


Extreme hunger

After experiencing prolonged significant calorie deficits, people often undergo extreme hunger (hyperphagia). Once weight is regained in both fat and muscle mass, their hunger usually returns to normalized levels. This process of regaining weight takes longer for fat-free/muscle mass which leads to a "fat overshoot" or "overshoot weight". This causes patient's body fat levels to be greater than before the disorder. This kind of process for hunger normalization varies between patient and could last anywhere from a few months to multiple years.


Refeeding syndrome

Treatment professionals tend to be conservative with refeeding in anorexic patients due to the risk of refeeding syndrome (RFS), which occurs when a malnourished person is refed too quickly for their body to be able to adapt. Two of the most common indicators that RFS is occurring are hypophosphatemia, low phosophate levels and hypokalemia, low potassium levels. RFS is most likely to happen in severely or extremely underweight anorexics, as well as when medical comorbidities, such as infection or cardiac failure, are present. In these circumstances, it is recommended to start refeeding more slowly but to build up rapidly as long as RFS does not occur. Recommendations on energy requirements in the most medically compromised patients vary, from 5–10 kcal/kg/day to 1900 kcal/day. This risk-averse approach can lead to underfeeding, which results in poorer outcomes for short- and long-term recovery.


Medication

Pharmaceuticals have limited benefit for anorexia itself. There is a lack of good information from which to make recommendations concerning the effectiveness of antidepressants in treating anorexia. Administration of olanzapine has been shown to result in a modest but statistically significant increase in body weight of anorexia nervosa patients. Other types of medication that can be used to treat Anorexia Nervosa are Prozac and Zyprexa. Prozac is a type of Selective Serotonin Reuptake Inhibitor which can be used to maintain a healthy weight in patients once they reach a healthy weight while Zyprexa is used to calm obsessive thinking and increase weight gain in patients.


Admission to hospital

Patients with AN may be deemed to have a Insight#Psychiatry, lack of insight regarding the necessity of treatment, and thus may be Involuntary treatment, involuntarily treated without their consent. AN has a high mortality and patients admitted in a severely ill state to medical units are at particularly high risk. Diagnosis can be challenging, risk assessment may not be performed accurately, consent and the need for compulsion may not be assessed appropriately, refeeding syndrome may be missed or poorly treated and the behavioural and family problems in AN may be missed or poorly managed. Guidelines published by the Royal College of Psychiatrists recommend that medical and psychiatric experts work together in managing severely ill people with AN.


Experience of treatment

Patients involved in treatment sometimes felt that treatment focused on biological aspects of body weight and eating behaviour change rather than their perceptions or emotional state. Patients felt that a therapists trust in them shown by being treated as a complete person with their own capacities was significant. Some patients defined Recovery model, recovery from AN in terms of reclaiming a lost Identity (social science), identity. Additionally, access to timely treatment can be hindered by systemic challenges within the medical system. Some individuals have reported experiencing delays in treatment, particularly when transitioning from adolescence to adulthood. Healthcare workers involved in the treatment of anorexia reported frustration and anger to setbacks in treatment and noncompliance and were afraid of patients dying. Some healthcare workers felt that they did not understand the treatment and that medical doctors were making decisions. They may feel powerless to improve a patient's situation and deskilled as a result. Healthcare workers involved in monitoring patients consumption of food felt watched themselves. Healthcare workers often feel a degree of moral dissonance of not being in control of outcomes which they may protect against by focusing on individual tasks, avoiding identifying with patients (for example by making their eating behavior very different and not sharing personal information with patients), and blaming patients for their distress. Healthcare workers would inflexibly follow process to avoid responsibility. Healthcare workers attempted to reach balance by gradually giving patients back control avoiding feeling sole responsibility for outcomes, being mindful of their emotional state, and trying to view eating disorders as external from patients.


Prognosis

AN has the highest mortality rate of any psychological disorder. The mortality rate is 11 to 12 times standardized mortality ratio, greater than in the general population, and the suicide risk is 56 times higher. Half of women with AN achieve a full recovery, while an additional 20–30% may partially recover. Not all people with anorexia recover completely: about 20% develop anorexia nervosa as a chronic disorder. If anorexia nervosa is not treated, serious complications such as heart conditions and kidney failure can arise and eventually lead to death. The average number of years from onset to remission of AN is seven for women and three for men. After ten to fifteen years, 70% of people no longer meet the diagnostic criteria, but many still continue to have eating-related problems. People who have autism recover more slowly, probably due to autism's effects on thinking patterns, such as reduced cognitive flexibility.
Alexithymia Alexithymia, also called emotional blindness, is a neuropsychological phenomenon characterized by significant challenges in recognizing, expressing, feeling, sourcing, and describing one's emotions. It is associated with difficulties in attachme ...
(inability to identify and describe one's own emotions) influences treatment outcome. Recovery is also viewed on a spectrum rather than black and white. According to the Morgan-Russell criteria, individuals can have a good, intermediate, or poor outcome. Even when a person is classified as having a "good" outcome, weight only has to be within 15% of average, and normal menstruation must be present in females. The good outcome also excludes psychological health. Recovery for people with anorexia nervosa is undeniably positive, but recovery does not mean a return to normal.


Complications

Anorexia nervosa can have serious implications if its duration and severity are significant and if onset occurs before the completion of growth, pubertal maturation, or the attainment of peak bone mass. Complications specific to adolescents and children with anorexia nervosa can include growth retardation, as height gain may slow and can stop completely with severe weight loss or chronic malnutrition. In such cases, provided that growth potential is preserved, height increase can resume and reach full potential after normal intake is resumed. Height potential is normally preserved if the duration and severity of illness are not significant or if the illness is accompanied by delayed bone age (especially prior to a bone age of approximately 15 years), as hypogonadism may partially counteract the effects of undernutrition on height by allowing for a longer duration of growth compared to controls. Appropriate early treatment can preserve height potential, and may even help to increase it in some post-anorexic subjects, due to factors such as long-term reduced estrogen-producing
adipose tissue Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothel ...
levels compared to premorbid levels. In some cases, especially where onset is before puberty, complications such as stunted growth and pubertal delay are usually reversible. Anorexia nervosa causes alterations in the female reproductive system; significant weight loss, as well as psychological stress and intense exercise, typically results in a secondary amenorrhea, cessation of menstruation in women who are past puberty. In patients with anorexia nervosa, there is a reduction of the secretion of gonadotropin releasing hormone in the central nervous system which prevents ovulation. Anorexia nervosa can also result in pubertal delay or arrest. Both height gain and pubertal development are dependent on the release of growth hormone and gonadotropins (LH and FSH) from the pituitary gland. Suppression of gonadotropins in people with anorexia nervosa has been documented. Typically, growth hormone (GH) levels are high, but levels of IGF-1, the downstream hormone that should be released in response to GH are low; this indicates a state of "resistance" to GH due to chronic starvation. IGF-1 is necessary for bone formation, and decreased levels in anorexia nervosa contribute to a loss of bone density and potentially contribute to osteopenia or
osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...
. Anorexia nervosa can also result in reduction of peak bone mass. Buildup of bone is greatest during adolescence, and if onset of anorexia nervosa occurs during this time and stalls puberty, low bone mass may be permanent. Hepatic steatosis, or fatty infiltration of the liver, can also occur, and is an indicator of malnutrition in children. Neurological disorders that may occur as complications include seizures and tremors. Wernicke encephalopathy, which results from vitamin B1 deficiency, has been reported in patients who are extremely malnourished; symptoms include confusion, ophthalmoparesis, problems with the muscles responsible for eye movements and ataxia, abnormalities in walking gait. The most common gastrointestinal complications of anorexia nervosa are Gastroparesis, delayed stomach emptying and
constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The Human feces, stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the ...
, but also include elevated liver function tests, diarrhea, acute pancreatitis, gastroesophageal reflux disease (GERD), dysphagia, difficulty swallowing, and, rarely, superior mesenteric artery syndrome. Acid exposure from GERD and self-induced vomiting can cause dental problems, such as dental erosion, tooth enamel erosion and gingivitis, gum disease. Delayed stomach emptying, or gastroparesis, often develops following food restriction and weight loss; the most common symptom is bloating with gas and abdominal distension, and often occurs after eating. Other symptoms of gastroparesis include early satiety, fullness, nausea, and vomiting. The symptoms may inhibit efforts at eating and recovery, but can be managed by limiting high-fiber foods, using liquid nutritional supplements, or using metoclopramide to increase emptying of food from the stomach. Gastroparesis generally resolves when weight is regained.


Cardiac complications

Anorexia nervosa increases the risk of sudden cardiac death, though the precise cause is unknown. Cardiac complications include structural and functional changes to the heart. Some of these cardiovascular changes are mild and are reversible with treatment, while others may be life-threatening. Cardiac complications can include cardiac arrhythmia, arrhythmias, bradycardia, abnormally slow heart beat, low blood pressure, Atrophy, decreased size of the heart muscle, reduced Stroke volume, heart volume, mitral valve prolapse, myocardial fibrosis, and pericardial effusion. Abnormalities in conduction and repolarization of the heart that can result from anorexia nervosa include QT prolongation, increased QT interval, QT dispersion, conduction delays, and junctional escape rhythms. Electrolyte abnormalities, particularly hypokalemia and hypomagnesemia, can cause anomalies in the electrical activity of the heart, and result in life-threatening arrhythmias. Hypokalemia most commonly results in patients with anorexia when restricting is accompanied by purging (induced vomiting or laxative use). Hypotension (low blood pressure) is common, and symptoms include fatigue and weakness. Orthostatic hypotension, a marked decrease in blood pressure when standing from a supine position, may also occur. Symptoms include lightheadedness upon standing, weakness, and cognitive impairment, and may result in Syncope (medicine), fainting or near-fainting. Orthostasis in anorexia nervosa indicates worsening cardiac function and may indicate a need for hospitalization. Hypotension and orthostasis generally resolve upon recovery to a normal weight. The weight loss in anorexia nervosa also causes atrophy of cardiac muscle. This leads to decreased cardiac output, ability to pump blood, a reduction in the ability to sustain exercise, a diminished ability to increase blood pressure in response to exercise, and a subjective feeling of fatigue. Some individuals may also have a decrease in cardiac contractility. Cardiac complications can be life-threatening, but the heart muscle generally improves with weight gain, and the heart normalizes in size over weeks to months, with recovery. Atrophy of the myocardium, heart muscle is a marker of the severity of the disease, and while it is reversible with treatment and refeeding, it is possible that it may cause permanent, microscopic changes to the heart muscle that increase the risk of sudden cardiac death. Individuals with anorexia nervosa may experience chest pain or palpitations; these can be a result of mitral valve prolapse. Mitral valve prolapse occurs because the size of the heart muscle decreases while the tissue of the mitral valve remains the same size. Studies have shown rates of mitral valve prolapse of around 20 percent in those with anorexia nervosa, while the rate in the general population is estimated at 2–4 percent. It has been suggested that there is an association between mitral valve prolapse and sudden cardiac death, but it has not been proven to be causative, either in patients with anorexia nervosa or in the general population.


Relapse

Rates of relapse after treatment range 30–72% over a period of 2–26 months, with a rate of approximately 50% in 12 months after weight restoration. Relapse occurs in approximately a third of people in hospital, and is greatest in the first six to eighteen months after release from an institution. BMI or measures of body fat and leptin levels at discharge were the strongest predictors of relapse, as well as signs of eating psychopathology at discharge. Duration of illness, age, severity, the proportion of AN binge-purge subtype, and presence of comorbidities are also contributing factors.


Epidemiology

Anorexia is estimated to occur in 0.9% to 4.3% of women and 0.2% to 0.3% of men in Western countries at some point in their life. About 0.4% of young females are affected in a given year and it is estimated to occur three to ten times less commonly in males. The cause of this disparity is not well-established but is thought to be linked to both biological and socio-cultural factors. Rates in most of the developing world are unclear. Often it begins during the teen years or young adulthood. Medical students are a high risk group, with an overall estimated prevalence of 10.4% globally. The lifetime rate of atypical anorexia nervosa, a form of ED-NOS in which the person loses a significant amount of weight and is at risk for serious medical complications despite having a higher body-mass index, is much higher, at 5–12%. Additionally, a UCSF study showed severity of illness is independent of current BMI, and "patients with large, rapid, or long-duration of weight loss were more severely ill regardless of their current weight." While anorexia became more commonly diagnosed during the 20th century it is unclear if this was due to an increase in its frequency or simply better diagnosis. Most studies show that since at least 1970 the incidence of AN in adult women is fairly constant, while there is some indication that the incidence may have been increasing for girls aged between 14 and 20.


Underrepresentation

In non-Westernized countries, including those in Africa (excluding South Africa), eating disorders are less frequently reported and studied compared to Western countries, with available data mostly limited to case reports and isolated studies rather than prevalence investigations. Theories to explain these lower rates of eating disorders, lower reporting, and lower research rates in these countries include the attention to effects of Westernization, westernisation and culture change on the prevalence of anorexia. Athletes are often overlooked as anorexic. Research emphasizes the importance to take athletes' diet, weight and symptoms into account when diagnosing anorexia, instead of just looking at weight and BMI. For athletes, ritualized activities such as weigh-ins place emphasis on gaining and losing large amounts of weight, which may promote the development of eating disorders among them. Furthermore, the competitive mindset of elite athletes makes them especially vulnerable to anorexia nervosa. The disorder is often largely rooted in a desire to maintain control over one's own life. The highly competitive mindset that athletic pursuits can easily translate to the world of disordered eating. Eating becomes "like a game" or "challenge", where the athlete is completely focused on "winning the game"; one elite swimmer with severe anorexia nervosa recalls that "it was always about losing more" and she "never wanted the game to be over".


Males

While anorexia nervosa is more commonly found in women, it can also affect men, with a lifetime prevalence of 0.3% in men. However, a lack of awareness of eating disorders in males may lead to underdiagnosis and underreporting. This can include a lack of knowledge about what kinds of behaviors males with eating disorders might display, as they differ slightly from those found in females, with a 2009 survey showing that females are more inclined to report fasting, body checking, and body avoidance, whereas males are more prone to report overeating. Due to this limited knowledge of how anorexia nervosa is presented in males, it often takes men longer to be diagnosed and receive treatment than women. An additional difference is in the use of supplements to affect bodyweight, with women being more prone to using
diet pills Anti-obesity medication or weight loss medications are pharmacological agents that reduce or control excess body fat. These medications alter one of the fundamental processes of the human anatomy, human body, body weight, weight regulation, by ...
and men being more prone to using anabolic steroids. Moreover, men who exhibit symptoms of anorexia may not meet the BMI criteria outlined in the DSM-IV due to having more muscle mass and therefore a higher bodyweight. Consequently, a subclinical diagnosis, such as ''Eating Disorder Not Otherwise Specified'' (ED-NOS) in the DSM-IV or ''Other Specified Feeding or Eating Disorder'' (OSFED) in the DSM-5, is often made instead. Men with anorexia may also experience body dysmorphia, reporting their bodies to be twice as large than in actuality, and body dissatisfaction, especially with regard to muscularity and body composition. Men tend to place more emphasis on a muscular build as opposed to pursuing thinness. As in the case of women, men are more prone to develop an eating disorder if their occupation or sport emphasizes having a slim physique or lighter weight, like modeling, dancing, horse racing, wrestling, and
gymnastics Gymnastics is a group of sport that includes physical exercises requiring Balance (ability), balance, Strength training, strength, Flexibility (anatomy), flexibility, agility, Motor coordination, coordination, artistry and endurance. The movem ...
. Hormonal changes may also be observed in males with anorexia nervosa, with marked changes in their serum testosterone, luteinizing hormone, and follicle stimulating hormone. Such extreme endocrine disturbances can potentially result in
infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...
. Anorexic men are sometimes colloquially referred to as ''manorexic'' or as having ''bigorexia''.


Elderly

An increasing trend of anorexia among the elderly, termed "Anorexia of Aging," is observed, characterized by behaviors similar to those seen in typical anorexia nervosa but often accompanied by excessive laxative use. Most geriatric anorexia patients limit their food intake to dairy or grains, whereas an adolescent anorexic has a more general limitation. This eating disorder that affects older adults has two types – early onset and late onset. Early onset refers to a recurrence of anorexia in late life in an individual who experienced the disease during their youth. Late onset describes instances where the eating disorder begins for the first time late in life. The stimulus for anorexia in elderly patients is typically a loss of control over their lives, which can be brought on by many events, including moving into an Assisted living, assisted living facility. This is also a time when most older individuals experience a rise in conflict with family members, such as limitations on driving or limitations on personal freedom, which increases the likelihood of an issue with anorexia. There can be physical issues in the elderly that leads to anorexia of aging, including a decline in chewing ability, a decline in taste and smell, and a decrease in appetite. Psychological reasons for the elderly to develop anorexia can include depression and bereavement, and even an indirect attempt at suicide. There are also common comorbid psychiatric conditions with aging anorexics, including major depression, anxiety disorder, obsessive compulsive disorder, bipolar disorder, schizophrenia, and dementia. The signs and symptoms that go along with anorexia of aging are similar to what is observed in adolescent anorexia, including sudden weight loss, unexplained hair loss or dental problems, and a desire to eat alone. There are also several medical conditions that can result from anorexia in the elderly. An increased risk of illness and death can be a result of anorexia. There is also a decline in muscle and bone mass as a result of a reduction in protein intake during anorexia. Another result of anorexia in the aging population is irreparable damage to kidneys, heart or colon and an imbalance of electrolytes. Many assessments are available to diagnose anorexia in the aging community. These assessments include the Simplified Nutritional Assessment Questionnaire (SNAQ) and Functional Assessment of Anorexia/Cachexia Therapy (FAACT). Specific to the geriatric populace, the interRAI system identifies detrimental conditions in assisted living facilities and nursing homes. Even a simple screening for nutritional insufficiencies such as low levels of important vitamins, can help to identify someone who has anorexia of aging. Anorexia in the elderly should be identified by the retirement communities but is often overlooked, especially in patients with dementia. Some studies report that malnutrition is prevalent in nursing homes, with up to 58% of residents suffering from it, which can lead to the difficulty of identifying anorexia. One of the challenges with assisted living facilities is that they often serve bland, monotonous food, which lessens residents' desire to eat. The treatment for anorexia of aging is undifferentiated as anorexia for any other age group. Some of the treatment options include outpatient and inpatient facilities, antidepressant medication and behavioral therapy such as meal observation and discussing eating habits.


History

The history of anorexia nervosa begins with descriptions of religious fasting dating from the Hellenistic civilization, Hellenistic era and continuing into the medieval period. The medieval practice of self-starvation by women, including some young women, in the name of religious piety and purity also concerns anorexia nervosa; it is sometimes referred to as ''anorexia mirabilis.'' The earliest medical descriptions of anorexic illnesses are generally credited to English physician Richard Morton (physician), Richard Morton in 1689. Etymologically, ''anorexia'' is a term of Greek origin: (, prefix denoting negation) and (, "appetite"), translating literally to "a loss of appetite". In and of itself, this term does not have a harmful connotation, e.g., ''exercise-induced anorexia'' simply means that hunger is naturally suppressed during and after sufficiently intense exercise sessions. It is the adjective ''nervosa'' that indicates the functional and non-organic nature of the disorder, but this adjective is also often omitted when the context is clear. Despite the literal translation of anorexia, the feeling of hunger in anorexia nervosa is frequently present and the pathological control of this instinct is a source of satisfaction for the patients. The term "anorexia nervosa" was coined in 1873 by Sir William Gull, 1st Baronet, Sir William Gull, one of Queen Victoria's personal physicians. Gull published a seminal paper providing a number of detailed case descriptions of patients with anorexia nervosa. In the same year, French physician Charles Lasègue, Ernest-Charles Lasègue similarly published details of a number of cases in a paper entitled ''De l'Anorexie hystérique''. See also In the late 19th century anorexia nervosa became widely accepted by the medical profession as a recognized condition. Awareness of the condition was largely limited to the medical profession until the latter part of the 20th century, when German-American psychoanalyst Hilde Bruch published ''The Golden Cage: the Enigma of Anorexia Nervosa'' in 1978. Despite major advances in neuroscience, Bruch's theories tend to dominate popular thinking. A further important event was the death of the popular singer and drummer Karen Carpenter in 1983, which prompted widespread ongoing media coverage of eating disorders.


See also

* Body image (neuroscience), Body image * Eating recovery * Evolutionary psychiatry * Idée fixe (psychology), Idée fixe * Inedia * List of people with anorexia nervosa * National Association of Anorexia Nervosa and Associated Disorders * Muscle dysmorphia * Orthorexia nervosa * Pro-ana


References


Further reading

* * *


External links


National Association of Anorexia Nervosa and Associated Disorders

Society of Clinical Psychology—Anorexia
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