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Anhedonia is a diverse array of deficits in
hedonic Hedonism is a family of philosophical views that prioritize pleasure. Psychological hedonism is the theory that all human behavior is motivated by the desire to maximize pleasure and minimize pain. As a form of egoism, it suggests that people ...
function, including reduced motivation or ability to experience pleasure. While earlier definitions emphasized the inability to experience pleasure, anhedonia is currently used by researchers to refer to reduced motivation, reduced anticipatory pleasure (wanting), reduced consummatory pleasure (liking), and deficits in
reinforcement learning Reinforcement learning (RL) is an interdisciplinary area of machine learning and optimal control concerned with how an intelligent agent should take actions in a dynamic environment in order to maximize a reward signal. Reinforcement learnin ...
. In the ''
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition 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 ...
'' (DSM-5), anhedonia is a component of depressive disorders, substance-related disorders, psychotic disorders, and personality disorders, where it is defined by either a reduced ability to experience pleasure, or a diminished interest in engaging in previously pleasurable activities. While the ''International Statistical Classification of Diseases and Related Health Problems, Tenth Revision'' (ICD-10) does not explicitly mention anhedonia, the depressive symptom analogous to anhedonia as described in the DSM-5 is a loss of interest or pleasure.


Definition

While anhedonia was originally defined in 1896 by
Théodule-Armand Ribot Théodule-Armand Ribot (18 December 18399 December 1916) was a French psychologist. He was born at Guingamp, and was educated at the Lycée de St Brieuc. He is known as the founder of scientific psychology in France, and gave his name to Ribot's ...
as the reduced ability to experience pleasure, it has been used to refer to deficits in multiple facets of reward. Reconceptualizations of anhedonia highlight the independence of "wanting" and "liking". "Wanting" is a component of anticipatory positive affect, mediating both the motivation (i.e. incentive salience) to engage with reward, as well as the positive emotions associated with anticipating a reward. "Liking", though, is associated with the pleasure derived from consuming a reward. The consciousness of reward-related processes has also been used to categorize reward in the context of anhedonia, as studies comparing implicit behavior versus explicit self-reports demonstrate a dissociation of the two. Learning has also been proposed as an independent facet of reward that may be impaired in conditions associated with anhedonia, but empirical evidence dissociating learning from either "liking" or "wanting" is lacking. Anhedonia has also been used to refer to "affective blunting", "restricted range of affect", "emotional numbing", and "flat affect", particularly in the context of post-traumatic stress disorders. In PTSD patients, scales measuring these symptoms correlate strongly with scales that measure more traditional aspects of anhedonia, supporting this association.


Causes

Studies in clinical populations, healthy populations, and animal models have implicated a number of neurobiological substrates in anhedonia. Regions implicated in anhedonia include the
prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. It is the association cortex in the frontal lobe. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, ...
as a whole, particularly the orbitofrontal cortex (OFC), 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 ...
,
amygdala The amygdala (; : amygdalae or amygdalas; also '; Latin from Greek language, Greek, , ', 'almond', 'tonsil') is a paired nucleus (neuroanatomy), nuclear complex present in the Cerebral hemisphere, cerebral hemispheres of vertebrates. It is c ...
,
anterior cingulate cortex (ACC) 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 in c ...
,
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 ...
, and ventral tegmental area (VTA). Neuroimaging studies in humans have reported that deficits in consummatory aspects of reward are associated with abnormalities in the ventral striatum and medial prefrontal cortex, while deficits in anticipatory aspects of reward are related to abnormalities in hippocampal, dorsal ACC and prefrontal regions. These abnormalities are generally consistent with animal models, except for inconsistent findings with regard to the OFC. This inconsistency may be related to the difficulty in imaging the OFC due to its anatomical location, or the small number of studies performed on anhedonia; a number of studies have reported reduced activity in the OFC in schizophrenia and major depression, as well as a direct relationship between reduced activity and anhedonia. Researchers theorize that anhedonia may result from the breakdown in the brain's reward system, involving the
neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a Chemical synapse, synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotra ...
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 ...
. Anhedonia can be characterised as "impaired ability to pursue, experience and/or learn about pleasure, which is often, but not always accessible to conscious awareness". The conditions of akinetic mutism and
negative symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...
are closely related. In akinetic mutism, a stroke or other lesion to the anterior cingulate cortex causes reduction in movement (akinetic) and speech (mutism).


Occurrence


Major depressive disorder

Anhedonia occurs in roughly 70% of people with a major depressive disorder. It is a core symptom of
major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive depression (mood), low mood, low self-esteem, and anhedonia, loss of interest or pleasure in normally ...
, so individuals experiencing this symptom can be diagnosed with depression, even in the absence of low/depressed mood. The ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM) describes a "lack of interest or pleasure", but these can be difficult to discern given that people tend to become less interested in things that do not give them pleasure. The DSM criterion of weight loss is probably related, and many individuals with this symptom describe a lack of enjoyment of food. They can portray any of the non-psychotic symptoms and signs of depression.


Schizophrenia

Anhedonia is one of the
negative symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...
of
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 ...
. Although five domains are usually used to classify negative symptoms, factor analysis of questionnaires yield two factors, with one including deficits in pleasure and motivation. People with schizophrenia retrospectively report experiencing fewer positive emotions than healthy individuals, but "liking" or consummatory pleasure is intact in people with schizophrenia, as they report experiencing the same degree of positive affect when presented with rewarding stimuli. Neuroimaging studies support this behavioral observation, as most studies report intact responses in the reward system (i.e. ventral striatum, VTA) to simple rewards. However, studies on monetary rewards sometimes report reduced responsiveness. More consistent reductions are observed with regard to emotional response during reward anticipation, which is reflected in a reduced responsiveness of both cortical and subcortical components of the reward system. Schizophrenia is associated with reduced positive prediction errors (a normal pattern of response to an unexpected reward), which a few studies have demonstrated to be correlated with negative symptoms. People with schizophrenia demonstrate impairment in reinforcement learning tasks only when the task requires explicit learning, or is sufficiently complex. Implicit reinforcement learning, on the other hand, is relatively intact. These deficits may be related to dysfunction in the ACC, OFC and dlPFC leading to abnormal representation of reward and goals.


Substance-related disorders

Anhedonia is common in people who are dependent upon any one or more of a wide variety of drugs, including
alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...
,
opioids Opioids are a class of Drug, drugs that derive from, or mimic, natural substances found in the Papaver somniferum, opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, ...
,
cannabinoids Cannabinoids () are several structural classes of compounds found primarily in the ''Cannabis'' plant or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (delta-9-THC), the primary psychoa ...
, and
nicotine Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...
. Although anhedonia becomes less severe over time, it is a significant predictor of relapse.


Post-traumatic stress disorder

While post-traumatic stress disorder (PTSD) is associated with reduced motivation, part of the anticipatory "wanting", it is also associated with elevated sensation seeking, and no deficits in physiological arousal, or self-reported pleasure to positive stimuli. PTSD is also associated with blunted affect, which may be due to the high comorbidity with depression.


Parkinson's disease

Anhedonia occurs frequently in
Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...
, with rates between 7 and 45% being reported. Whether or not anhedonia is related to the high rates of depression in Parkinson's disease is unknown.


Bipolar depression

Anhedonia is also reported to appear in people with
bipolar depression Bipolar disorder (BD), previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that each last from days to weeks, and in some cases months. If the elevated m ...
.


Attention deficit hyperactivity disorder

Anhedonia may be associated with attention deficit hyperactivity disorder (
ADHD 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 ...
). Impairments of
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 ...
rgic and serotonergic function in the brain of those with ADHD result in dysregulation of reward processing, which can lead to anhedonia.


Sexual anhedonia

Sexual anhedonia in males is also known as "ejaculatory anhedonia". This condition means that a male will
ejaculate Ejaculation is the discharge of semen (the ''ejaculate''; normally containing sperm) from the penis through the urethra. It is the final stage and natural objective of male sexual stimulation, and an essential component of natural concepti ...
with no accompanying sense of pleasure. The condition is most frequently found in males, but females can experience lack of pleasure when the body goes through the
orgasm Orgasm (from Greek , ; "excitement, swelling"), sexual climax, or simply climax, is the sudden release of accumulated sexual excitement during the sexual response cycle, characterized by intense sexual pleasure resulting in rhythmic, involu ...
process, as well. Sexual anhedonia may be caused by: *
Hyperprolactinaemia Hyperprolactinaemia (also spelled hyperprolactinemia) is a condition characterized by abnormally high levels of prolactin in the blood. In women, normal prolactin levels average to about 13 ng/mL, while in men, they average 5 ng/mL. ...
* Hypoactive sexual desire disorder (HSDD), also called inhibited sexual desire * Low levels of the hormone
testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
* Spinal cord injury *
Multiple sclerosis Multiple sclerosis (MS) is an autoimmune disease resulting in damage to myelinthe insulating covers of nerve cellsin the brain and spinal cord. As a demyelinating disease, MS disrupts the nervous system's ability to Action potential, transmit ...
* Use of
SSRI Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions. SSRIs primarily work by ...
antidepressants or having used SSRI antidepressants in the past * Use (or previous use) of antidopaminergic neuroleptics (
anti-psychotic Antipsychotics, previously known as neuroleptics and major tranquilizers, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizoph ...
s) * Fatigue * Physical illness A neurological examination and blood tests are very unlikely to determine the cause of a specific case of sexual anhedonia. Patients may be prescribed sustained-release
bupropion Bupropion, formerly called amfebutamone, and sold under the brand name Wellbutrin among others, is an atypical antidepressant that is indicated in the treatment of major depressive disorder, seasonal affective disorder, and to support smo ...
to aid in treatment, which has been shown to relieve sexual dysfunction even in patients without depression.


Social anhedonia


Definition

Social anhedonia is defined as a disinterest in social contact and a lack of pleasure in social situations, and is characterized by social withdrawal. This characteristic typically manifests as an indifference to other people. In contrast to
introversion Extraversion and introversion are a central trait dimension in human personality theory. The terms were introduced into psychology by Carl Jung, though both the popular understanding and current psychological usage are not the same as Jung's o ...
, a nonpathological dimension of human personality, social anhedonia represents a deficit in the ability to experience
pleasure Pleasure is experience that feels good, that involves the enjoyment of something. It contrasts with pain or suffering, which are forms of feeling bad. It is closely related to value, desire and action: humans and other conscious animals find ...
. Additionally, social anhedonia differs from
social anxiety Social anxiety is the anxiety and fear specifically linked to being in social settings (i.e., interacting with others). Some categories of disorders associated with social anxiety include anxiety disorders, mood disorders, autism spectrum dis ...
in that social anhedonia is predominantly typified by diminished positive affect, while social anxiety is distinguished by both decreased
positive affect Positive affectivity (PA) is a human characteristic that describes how much people experience positive affects (sensations, emotions, sentiments); and as a consequence how they interact with others and with their surroundings. People with high po ...
and exaggerated
negative affect In psychology, negative affectivity (NA), or negative affect, is a personality variable that involves the experience of negative emotions and poor self-concept. Negative affectivity subsumes a variety of negative emotions, including anger, contem ...
. This trait is currently seen as a central characteristic, as well as a predictor, of
schizophrenia spectrum disorders A spectrum disorder is a disorder that includes a range of linked conditions, sometimes also extending to include singular symptoms and traits. The different elements of a spectrum either have a similar appearance or are thought to be caused by th ...
. It is also widely linked to
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 ...
disorder.


Signs and symptoms

* Decreased ability to experience interpersonal pleasure * Social withdrawal/isolation * Decreased capacity for social contact and interaction * Lack of close friends and intimate relationships, and decreased quality of those relationships * Poor social adjustment * Decreased positive affect *
Flat affect Reduced affect display, sometimes referred to as emotional blunting or emotional numbing, is a condition of reduced emotional reactivity in an individual. It manifests as a failure to express feelings either verbally or nonverbally, especially w ...
* Depressed mood * State-related anxiety


Background and early clinical observation

The term ''anhedonia'' is derived from the Greek ''an-'', "without" and ''hēdonē'', "pleasure". Interest in the nature of pleasure and its absence dates back to ancient Greek philosophers such as
Epicurus Epicurus (, ; ; 341–270 BC) was an Greek philosophy, ancient Greek philosopher who founded Epicureanism, a highly influential school of philosophy that asserted that philosophy's purpose is to attain as well as to help others attain tranqui ...
. The symptoms of anhedonia were introduced to the realm of psychopathology in 1809 by John Haslam, who characterized a patient with schizophrenia as indifferent to "those objects and pursuits which formerly proved sources of delight and instruction". The concept was formally coined by
Théodule-Armand Ribot Théodule-Armand Ribot (18 December 18399 December 1916) was a French psychologist. He was born at Guingamp, and was educated at the Lycée de St Brieuc. He is known as the founder of scientific psychology in France, and gave his name to Ribot's ...
and later used by psychiatrists Paul Eugen Bleuler and
Emil Kraepelin Emil Wilhelm Georg Magnus Kraepelin (; ; 15 February 1856 – 7 October 1926) was a German psychiatrist. H. J. Eysenck's Encyclopedia of Psychology identifies him as the founder of modern scientific psychiatry, psychopharmacology and psychiatric ...
to describe a core symptom of schizophrenia. In particular,
Sandor Rado Sandor Rado ( ; 8 January 1890, Kisvárda – 14 May 1972, New York City) was a Hungarian psychoanalyst of the second generation, who moved to the United States in the 1930s. According to Peter Gay, "Budapest produced some of the most conspicuo ...
postulated that schizotypes, or individuals with the schizophrenic phenotype, have two key genetic deficits, one related to the ability to feel pleasure (anhedonia) and one related to
proprioception Proprioception ( ) is the sense of self-movement, force, and body position. Proprioception is mediated by proprioceptors, a type of sensory receptor, located within muscles, tendons, and joints. Most animals possess multiple subtypes of propri ...
. In 1962, Meehl furthered Rado's theory through the introduction of the concept of schizotaxia, a genetically driven neural integrative defect thought to give rise to the personality type of
schizotypy In psychology, schizotypy is a theoretical concept that posits a continuum (theory), continuum of personality psychology, personality characteristics and experiences, ranging from normal dissociative, imaginative states to extreme states of mind ...
. Loren and Jean Chapman further distinguished between two types of anhedonia: Physical anhedonia, or a deficit in the ability to experience physical pleasure, and social, or a deficit in the ability to experience interpersonal pleasure. Recent research suggests that social anhedonia may represent a
prodrome In medicine, a prodrome is an early sign or symptom (or set of signs and symptoms, referred to as prodromal symptoms) that often indicates the onset of a disease before more diagnostically specific signs and symptoms develop. More specifically, it ...
of psychotic disorders. First-degree relatives of individuals with schizophrenia show elevated levels of social anhedonia; higher baseline scores of social anhedonia are associated with later development of schizophrenia. These findings provide support for the conjecture that it represents a genetic risk marker for schizophrenia-spectrum disorders. Additionally, elevated levels of social anhedonia in patients with schizophrenia have been linked to poorer social functioning. Socially anhedonic individuals perform worse on a number of neuropsychological tests than non-anhedonic participants, and show similar physiological abnormalities seen in patients with schizophrenia.


Comorbidity

Anhedonia is present in several forms of
psychopathology Psychopathology is the study of mental illness. It includes the signs and symptoms of all mental disorders. The field includes Abnormal psychology, abnormal cognition, maladaptive behavior, and experiences which differ according to social norms ...
and
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 ...
disorder.


Depression

Social anhedonia is observed in both depression and schizophrenia, but social anhedonia is a state related to the depressive episode and the other is a trait related to the personality construct associated with schizophrenia. These individuals both tend to score highly on self-report measures of social anhedonia. Blanchard, Horan, and Brown demonstrated that, although both the depression and the schizophrenia patient groups can look very similar in terms of social anhedonia cross-sectionally, over time as individuals with depression experience symptom remission, they show fewer signs of social anhedonia, while individuals with schizophrenia do not. Blanchard and colleagues (2011) found individuals with social anhedonia also had elevated rates of lifetime mood disorders including depression and
dysthymia Dysthymia ( ), known as persistent depressive disorder (PDD) in the DSM-5-TR and dysthymic disorder in ICD-11, is a psychiatric condition marked by symptoms that are similar to those of major depressive disorder, but which persist for at leas ...
compared to controls.


Social anxiety

As mentioned above, social anxiety and social anhedonia differ in important ways. Social anhedonia and social anxiety, though, are also often comorbid. People with social anhedonia may display increased social anxiety and be at increased risk for social phobias and generalized anxiety disorder. The exact relationship between social anhedonia and social anxiety, and whether one potentiates the other, has yet to be determined. Individuals with social anhedonia may display increased stress reactivity, meaning that they feel more overwhelmed or helpless in response to a stressful event compared to control subjects who experience the same type of stressor. This dysfunctional stress reactivity may correlate with hedonic capacity, providing a potential explanation for the increased anxiety symptoms experienced in people with social anhedonia. In an attempt to separate out social anhedonia from social anxiety, the Revised Social Anhedonia ScaleEckblad, M.L., Chapman, L.J., Chapman, J.P., & Mishlove, M. (1982)
The Revised Social Anhedonia Scale
. Unpublished test
didn't include items that potentially targeted social anxiety. However, more research must be conducted on the underlying mechanisms through which social anhedonia overlaps and interacts with social anxiety. The efforts of the "social processes" RDoC initiative will be crucial in differentiating between these components of social behavior that may underlie mental illnesses such as schizophrenia.


Primary relevance in schizophrenia and its spectrum disorders

Social anhedonia is a core characteristic of
schizotypy In psychology, schizotypy is a theoretical concept that posits a continuum (theory), continuum of personality psychology, personality characteristics and experiences, ranging from normal dissociative, imaginative states to extreme states of mind ...
, which is defined as a continuum of personality traits that can range from normal to disordered and contributes to risk for
psychosis In psychopathology, psychosis is a condition in which a person is unable to distinguish, in their experience of life, between what is and is not real. Examples of psychotic symptoms are delusions, hallucinations, and disorganized or inco ...
and
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 ...
. Social anhedonia is a dimension of both negative and positive schizotypy. Research has revealed that anhedonia reflects the diminished experience of pleasure, so individuals with schizophrenia reported that doing activities they previously found enjoyable is no longer enjoyable for them. It involves social and interpersonal deficits, but is also associated with cognitive slippage and disorganized speech, both of which fall into the category of positive schizotypy. Not all people with schizophrenia display social anhedonia and likewise, people who have social anhedonia may never be diagnosed with a schizophrenia-spectrum disorder if they do not have the positive and cognitive symptoms that are most frequently associated with most schizophrenia-spectrum disorders. Social anhedonia may be a valid predictor of future schizophrenia-spectrum disorders; young adults with social anhedonia perform in a similar direction to schizophrenia patients in tests of cognition and social behavior, showing potential predictive validity. Social anhedonia usually manifests in adolescence, possibly because of a combination of the occurrence of critical neuronal development and synaptic pruning of brain regions important for social behavior and environmental changes, when adolescents are in the process of becoming individuals and gaining more independence.


Treatment

No validated treatment for social anhedonia has been identified. Future research should focus on genetic and environmental risk factors to home in on specific brain regions and neurotransmitters that may be implicated in social anhedonia's cause, and could be targeted with medication or behavioral treatments. Social support may also play a valuable role in the treatment of social anhedonia. Blanchard et al. found that a greater number of social supports, as well as a greater perceived social support network, were related to fewer schizophrenia-spectrum symptoms and to better general functioning within the social anhedonia group. So far, no medicine has been developed to specifically target anhedonia.


Sex differences

In the general population, males score higher than females on measures of social anhedonia. This sex difference is stable throughout time (from adolescence into adulthood) and is also seen in people with schizophrenia-spectrum disorders. These results may reflect a more broad pattern of interpersonal and social deficits seen in schizophrenia-spectrum disorders. On average, males with schizophrenia are diagnosed at a younger age, have more severe symptoms, worse treatment prognosis, and a decrease in overall quality of life compared to females with the disorder. These results, coupled with the sex difference seen in social anhedonia, outline the necessity for research on genetic and hormonal characteristics that differ between males and females, and that may increase risk or resilience for mental illnesses such as schizophrenia.


Assessing social anhedonia

There are several self-report psychometric measures of
schizotypy In psychology, schizotypy is a theoretical concept that posits a continuum (theory), continuum of personality psychology, personality characteristics and experiences, ranging from normal dissociative, imaginative states to extreme states of mind ...
which each contain subscales related to social anhedonia: * Revised Social Anhedonia Scale – Chapman Psychosis Proneness Scales * No Close Friends Subscale – Schizotypal Personality Questionnaire * Introverted Anhedonia Subscale – Oxford–Liverpool Inventory of Feelings and Experiences


Genetic components

L.J. and J.P. Chapman were the first to discuss the possibility that social anhedonia may stem from a genetic vulnerability. The disrupted in schizophrenia 1 (''DISC1'') gene has been consistently associated with risk for, and cause of, schizophrenia-spectrum disorders and other mental illnesses. More recently,
DISC1 Disrupted in schizophrenia 1 is a protein that in humans is encoded by the ''DISC1'' gene. In coordination with a wide array of interacting partners, DISC1 has been shown to participate in the regulation of cell proliferation, differentiation, ...
has been associated with social anhedonia within the general population. Tomppo identified a specific DISC1
allele An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...
that is associated with an increase in characteristics of social anhedonia. They also identified a ''DISC1'' allele associated with decreased characteristics of social anhedonia, that was found to be preferentially expressed in women. More research needs to be conducted, but social anhedonia may be an important intermediate phenotype (
endophenotype In genetic epidemiology, endophenotype (or intermediate phenotype) is a term used to separate behavioral symptoms into more stable phenotypes with a clear genetic connection. By seeing the EP notion as a special case of a larger collection of mul ...
) between genes associated with risk for schizophrenia and phenotype of the disorder.


Neurobiological correlates

Researchers studying the neurobiology of social anhedonia posit that this trait may be linked to dysfunction of reward-related systems in the brain. This circuitry is critical for the sensation of pleasure, the computation of reward benefits and costs, determination of the effort required to obtain a pleasant stimulus, deciding to obtain that stimulus, and increasing motivation to obtain the stimulus. In particular, the ventral striatum and areas of the
prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. It is the association cortex in the frontal lobe. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, ...
(PFC), including the
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 ...
(OFC) and dorsolateral (dl) PFC, are critically involved in the experience of pleasure and the
hedonic Hedonism is a family of philosophical views that prioritize pleasure. Psychological hedonism is the theory that all human behavior is motivated by the desire to maximize pleasure and minimize pain. As a form of egoism, it suggests that people ...
perception of rewards. With regards to neurotransmitter systems,
opioid Opioids are a class of Drug, drugs that derive from, or mimic, natural substances found in the Papaver somniferum, opium poppy plant. Opioids work on opioid receptors in the brain and other organs to produce a variety of morphine-like effects, ...
,
gamma-aminobutyric acid GABA (gamma-aminobutyric acid, γ-aminobutyric acid) is the chief inhibitory neurotransmitter in the developmentally mature mammalian central nervous system. Its principal role is reducing neuronal excitability throughout the nervous system. GA ...
, and endocannabinoid systems in the
nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for ' nucleus adjacent to the septum') is a region in the basal forebrain rostral to the preoptic area of the hypo ...
,
ventral pallidum The ventral pallidum (VP) is a structure within the basal ganglia of the brain. It is an output nucleus whose fibres project to thalamic nuclei, such as the ventral anterior nucleus, the ventral lateral nucleus, and the medial dorsal nucleus ...
, and OFC mediate the hedonic perception of rewards. Activity in the PFC and ventral striatum have been found to be decreased in anhedonic individuals with
major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive depression (mood), low mood, low self-esteem, and anhedonia, loss of interest or pleasure in normally ...
and schizophrenia. However, schizophrenia may be less associated with decreased hedonic capacity and more with deficient reward appraisal.


Specific musical anhedonia

Recent studies have found people who do not have any issue processing musical tones or beat, yet receive no pleasure from listening to music. Specific musical anhedonia is distinct from melophobia, the fear of music.


See also

*
Avolition Avolition or amotivation, as a symptom of various forms of psychopathology, is the decrease in the ability to initiate and persist in self-directed purposeful activities. Such activities that appear to be neglected usually include routine activit ...
*
Disorders of diminished motivation Disorders of diminished motivation (DDM) are a group of disorders involving diminished motivation and associated emotions. Many different terms have been used to refer to diminished motivation. Often however, a spectrum is defined encompassing ...
*
Dysthymia Dysthymia ( ), known as persistent depressive disorder (PDD) in the DSM-5-TR and dysthymic disorder in ICD-11, is a psychiatric condition marked by symptoms that are similar to those of major depressive disorder, but which persist for at leas ...


References


External links


Anhedonia – Bipolar Disorder Symptoms


{{Authority control Major depressive disorder Mood disorders Pleasure Symptoms and signs of mental disorders Disorders of diminished motivation Symptoms or signs involving mood or affect