Altered Perception
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An altered state of consciousness (ASC), also called an altered state of mind, altered mental status (AMS) or mind alteration, is any condition which is significantly different from a normal waking state. It describes induced changes in one's mental state, almost always temporary. A synonymous phrase is "altered state of awareness".


History

By 1892, the expression was in use in relation to
hypnosis Hypnosis is a human condition involving focused attention (the selective attention/selective inattention hypothesis, SASI), reduced peripheral awareness, and an enhanced capacity to respond to suggestion.In 2015, the American Psychological ...
, though there is an ongoing debate as to whether hypnosis is to be identified as an ASC according to its modern definition. The next retrievable instance, by Max Mailhouse from his 1904 presentation to conference, however, is unequivocally identified as such, as it was in relation to
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
, and is still used today. In academia, the expression was used as early as 1966 by Arnold M. Ludwig and brought into common usage from 1969 by
Charles Tart Charles T. Tart (April 29, 1937 – March 5, 2025) was an American psychologist and parapsychologist known for his psychological work on the nature of consciousness (particularly altered states of consciousness), as one of the founders of the f ...
.


Definitions

There is no general definition of an altered state of consciousness, as any definitional attempt would first have to rely on a definition of a normal state of consciousness. Attempts to define the term can however be found in philosophy, psychology and neuroscience. There is no final consensus on what the most accurate definition is. The best-established and latest definitions are provided below. Arnold M. Ludwig attempted a first definition in 1966. Starting from this,
Charles Tart Charles T. Tart (April 29, 1937 – March 5, 2025) was an American psychologist and parapsychologist known for his psychological work on the nature of consciousness (particularly altered states of consciousness), as one of the founders of the f ...
focuses his definition on the subjective experience of a state of consciousness and its deviation from a normal waking state. Farthing's definition of an altered state of consciousness (ASC) is based on Charles Tart's terminology. Charles Tart described an altered state of consciousness as a profound change in the "overall pattern of subjective experiences". In order to define an ASC, Tart focuses on the importance of subjective experience. Farthing adds to his definition that an ASC is short-termed or at least reversible and that it might not even be recognized as an ASC at that moment. His definition relies only on subjective experience, leaving aside behavioral changes and physiological response. He lists fourteen dimensions of changed subjective experience. To account for an ASC, multiple dimensions need to be altered. A working definition for empirical research based on these previous definitions was by Schmidt in 2016:


History


History of utilization of ASCs

Altered states of consciousness might have been employed by humans as early as 30,000 years ago. Mind-altering plants and/or excessive dancing were used to attain an
ecstatic Ecstasy () is a subjective experience of total involvement of the subject with an object of their awareness. In classical Greek literature, it refers to removal of the mind or body "from its normal place of function." Total involvement with a ...
or mystic state. Examples of early religious use of altered states of consciousness are the rites of
Dionysus In ancient Greek religion and Greek mythology, myth, Dionysus (; ) is the god of wine-making, orchards and fruit, vegetation, fertility, festivity, insanity, ritual madness, religious ecstasy, and theatre. He was also known as Bacchus ( or ; ...
and the
Eleusinian Mysteries The Eleusinian Mysteries () were initiations held every year for the Cult (religious practice), cult of Demeter and Persephone based at the Panhellenic Sanctuary of Eleusis in ancient Greece. They are considered the "most famous of the secret rel ...
, as well as
yoga Yoga (UK: , US: ; 'yoga' ; ) is a group of physical, mental, and spiritual practices or disciplines that originated with its own philosophy in ancient India, aimed at controlling body and mind to attain various salvation goals, as pra ...
and
meditation Meditation is a practice in which an individual uses a technique to train attention and awareness and detach from reflexive, "discursive thinking", achieving a mentally clear and emotionally calm and stable state, while not judging the meditat ...
. Followers of various
shaman Shamanism is a spiritual practice that involves a practitioner (shaman) interacting with the spirit world through altered states of consciousness, such as trance. The goal of this is usually to direct spirits or spiritual energies into ...
ic traditions "enter altered states of consciousness in order to serve their community."
Terence McKenna Terence Kemp McKenna (November 16, 1946–April 3, 2000) was an American ethnobotanist and mystic who advocated for the responsible use of naturally occurring psychedelic plants and mushrooms. He spoke and wrote about a variety of subjects, ...
has suggested that the use of
psychedelic mushrooms A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom. The standard for the name "mushroom" is ...
in prehistoric times has led to the "evolution of human language and symbol use". Some theorists propose that mind-altering substances, such as
soma Soma may refer to: Businesses and brands * SOMA (architects), a New York–based firm of architects * Soma (company), a company that designs eco-friendly water filtration systems * SOMA Fabrications, a builder of bicycle frames and other bicycle ...
, might have pushed the formation of some of the world's main religions. Meditation in its various forms is being rediscovered by modern psychology because of its therapeutic potential and its ability to "enable the activity of the mind to settle down". In psychotherapy, techniques like
hypnosis Hypnosis is a human condition involving focused attention (the selective attention/selective inattention hypothesis, SASI), reduced peripheral awareness, and an enhanced capacity to respond to suggestion.In 2015, the American Psychological ...
and meditation support psychological processes.


History of scientific study

Due to the
behaviourist Behaviorism is a systematic approach to understand the behavior of humans and other animals. It assumes that behavior is either a reflex elicited by the pairing of certain antecedent (behavioral psychology), antecedent stimuli in the environmen ...
paradigm in psychology altered states of consciousness were dismissed as a field of scientific inquiry during the early 20th century. They were pathologized and merely seen as symptoms of intoxication or
demonic possession Spirit Possession is an altered state of consciousness and associated behaviors which are purportedly caused by the control of a human body and its functions by Supernatural#Spirit, spirits, ghosts, demons, angels, or Deity, gods. The concept ...
. Their return into psychology began with Wiliam James' interest into a variety of altered states, such as "mystical experiences and drug-induced states". James' investigations into first-person-subjective-experience contributed to the reconsideration of introspection as a valuable research method in the academic community. The social change of the turbulent 1960s has decisively led to a change of the scientific perspective to the point that introspection as a scientific method and ASCs as valid realms of experience became more widely accepted. Foundations for the research have been laid out by various scientists such as
Abraham Maslow Abraham Harold Maslow ( ; April 1, 1908 – June 8, 1970) was an American psychologist who created Maslow's hierarchy of needs, a theory of psychological health predicated on fulfilling innate human needs in priority, culminating in self-actua ...
, Walter N. Pahnke,
Stanislav Grof Stanislav Grof (born July 1, 1931) is a Czech-born American psychiatrist. Grof is one of the principal developers of transpersonal psychology and research into the use of non-ordinary states of consciousness for purposes of psychological hea ...
and Charles Tart. They focused on seemingly beneficial aspects of ASCs such as their potential to "promote creativity or treat addiction". Rather oppressive states such as dissociation from trauma were neglected. The findings of the famous Good Friday Experiment by Pahnke suggest that
mystical Mysticism is popularly known as becoming one with God or the Absolute, but may refer to any kind of ecstasy or altered state of consciousness which is given a religious or spiritual meaning. It may also refer to the attainment of insight ...
experiences can be triggered by
psilocybin Psilocybin, also known as 4-phosphoryloxy-''N'',''N''-dimethyltryptamine (4-PO-DMT), is a natural product, naturally occurring tryptamine alkaloid and Investigational New Drug, investigational drug found in more than List of psilocybin mushroom ...
. Later investigations by
Rick Doblin Richard Elliot Doblin (born November 30, 1953) is an American psychedelic drug advocate who is the founder and president of the Multidisciplinary Association for Psychedelic Studies (MAPS). Early life and education Rick Doblin grew up in Skokie ...
found that participants valued those experiences as "spiritual high points of their lives". In the midst of the rise of new-age subculture Stanislav Grof and others formed the new field of
transpersonal psychology Transpersonal psychology, or spiritual psychology, is an area of psychology that seeks to integrate the spiritual and transcendent human experiences within the framework of modern psychology. Evolving from the humanistic psychology movement, ...
, which emphasized "the importance of individual human experience, validity of mystical and
spiritual experience A religious experience (sometimes known as a spiritual experience, sacred experience, mystical experience) is a subjective experience which is interpreted within a religious framework. The concept originated in the 19th century, as a defense ag ...
, interconnectedness of self with others and the world and potential of self-transformation". Abraham Maslow's research on
peak experience A peak experience is an altered state of consciousness characterized by euphoria, often achieved by self-actualizing individuals. The concept was originally developed by psychologist Abraham Maslow in mid-1940s and term was coined by him in 1956 ...
s, as moments of "highest happiness and fulfillment", further contributed to the depathologization of altered states. A first summary of the existing literature was carried out by Charles T. Tart in his book ''Altered States of Consciousness'', which led to a more common use of the term. Tart coined the key terms ''discrete'' and ''baseline'' states of consciousness, and thought about a general classification system for ASCs. He also called for "state specific sciences" in which researchers should do science on ASCs from within such states.


Classification

A classification of Altered States of Consciousness is helpful for comparing or differentiating induced ASCs and other variations of consciousness. Various researchers have attempted the classification into a broader framework. The attempts of classification discussed in the following focus on slightly different aspects of ASCs. Several authors suggested classification schemata with regard to the genesis of altered states and with regard to the type of experiences: A classification with five categories was suggested by Dieter Vaitl to distinguish ASCs according to how they were induced: * Pathological (Epilepsy, brain damage) * Pharmacological (psychoactive substances) * Physical and physiological (fasting and sex) * Psychological (music, meditation, hypnosis) * Spontaneous (day-dreaming and near death experience) Vaitl further suggests four basic aspects of experiences: (1) activation (2) awareness span (3) self-awareness (4) sensory dynamics. Alternatively Roland Fischer suggests a classification along ergotropic (i.e., ecstasy) or trophotropic (i.e., meditation) properties. The work of Adolph Dittrich aimed to empirically determine common underlying dimensions of consciousness alterations induced by different methods, such as drugs or non-pharmacological methods. He suggested three basic dimensions, which were termed: (1) oceanic boundlessness (2) dread of
ego dissolution Ego death is a "complete loss of subjective self-identity". The term is used in various intertwined contexts, with related meanings. The 19th-century philosopher and psychologist William James uses the synonymous term "self-surrender", and Jungi ...
(3) visionary restructuralization. Further,
Ken Wilber Kenneth Earl Wilber II (born January 31, 1949) is an American theorist and writer on transpersonal psychology and his own integral theory, a four-quadrant grid which purports to encompass all human knowledge and experience. Starting publishing ...
proposes a multidimensional system and adds that the individual experience of an ASC is shaped by a person's unique psychological development. Michael Winkelman argues that there are four different "modes of consciousness": (1) the waking mode (2) the deep sleep mode (3) the REM sleep / dreaming mode (4) the integrative mode. Within this framework, many ASCs (psychedelics, hypnosis, meditation, etc.) are defined as belonging to the integrative mode.


Induction methods


Pharmacological

An altered state of consciousness may be defined as a short-term change in the general configuration of one's individual experience, such that the rational functioning is clearly altered from one's usual state of consciousness. There are many ways that one's consciousness can be altered, such as by using
psychoactive drugs A psychoactive drug, psychopharmaceutical, mind-altering drug, consciousness-altering drug, psychoactive substance, or psychotropic substance is a chemical substance that alters psychological functioning by modulating central nervous system acti ...
, which are defined as chemical substances that pass through the blood-brain barrier and disturb brain function, causing changes in
awareness In philosophy and psychology, awareness is the perception or knowledge of something. The concept is often synonymous with consciousness. However, one can be aware of something without being explicitly conscious of it, such as in the case of bli ...
,
attitude Attitude or Attitude may refer to: Philosophy and psychology * Attitude (psychology), a disposition or state of mind ** Attitude change * Propositional attitude, a mental state held towards a proposition Science and technology * Orientation ...
,
consciousness Consciousness, at its simplest, is awareness of a state or object, either internal to oneself or in one's external environment. However, its nature has led to millennia of analyses, explanations, and debate among philosophers, scientists, an ...
, and
behavior Behavior (American English) or behaviour (British English) is the range of actions of Individual, individuals, organisms, systems or Artificial intelligence, artificial entities in some environment. These systems can include other systems or or ...
.
Cannabis ''Cannabis'' () is a genus of flowering plants in the family Cannabaceae that is widely accepted as being indigenous to and originating from the continent of Asia. However, the number of species is disputed, with as many as three species be ...
is a psychoactive drug that is known to alter the state of consciousness. Cannabis alters mental activity, memory, and pain perception. One who is under the influence of cannabis may experience degrees of
paranoia Paranoia is an instinct or thought process that is believed to be heavily influenced by anxiety, suspicion, or fear, often to the point of delusion and irrationality. Paranoid thinking typically includes persecutory beliefs, or beliefs of co ...
, increased sensitivity, and delayed reactions not normal for their usual conscious state. A 2009 review of
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 cannabis studies concluded that "frequent cannabis users appear to have higher levels of anxiety than non-users," and that "a considerable number of subjects developed anxiety disorders before the first symptoms of cannabis dependence." That led researchers to believe that anxiety-prone people tend to use cannabis as a self-prescribed anxiety medicine, opposing the idea that cannabis is what's causing the anxiety.
MDMA 3,4-Methylenedioxymethamphetamine (MDMA), commonly known as ecstasy (tablet form), and molly (crystal form), is an empathogen–entactogenic drug with stimulant and minor Psychedelic drug, psychedelic properties. In studies, it has been used ...
(ecstasy) is a drug that also alters one's state of consciousness. The state of consciousness brought about by MDMA ingestion includes a rise in positive feelings and a reduction in negative feelings (Aldridge, D., & Fachner, J. ö. 2005). Users' emotions are increased and inhibitions lowered, often accompanied by a sensation of
intimacy An intimate relationship is an interpersonal relationship that involves emotional or physical closeness between people and may include sexual intimacy and feelings of romance or love. Intimate relationships are interdependent, and the member ...
or connection with other people.
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, ...
are a class of drugs that alter consciousness. Examples of opioids include heroin,
morphine Morphine, formerly also called morphia, is an opiate that is found naturally in opium, a dark brown resin produced by drying the latex of opium poppies (''Papaver somniferum''). It is mainly used as an analgesic (pain medication). There are ...
,
hydrocodone Hydrocodone, also known as dihydrocodeinone, is a semi-synthetic opioid used to treat pain and as a cough suppressant. It is taken by mouth. Typically, it is dispensed as the combination acetaminophen/hydrocodone or ibuprofen/hydrocodone fo ...
, and
oxycodone Oxycodone, sold under the brand name Roxicodone and OxyContin (which is the extended-release form) among others, is a semi-synthetic opioid used medically for the treatment of moderate to severe pain. It is highly addictive and is a commonly ...
. Opioids produce analgesia and often feelings of
euphoria Euphoria ( ) is the experience (or affect) of pleasure or excitement and intense feelings of well-being and happiness. Certain natural rewards and social activities, such as aerobic exercise, laughter, listening to or making music and da ...
in users. Opioid abuse may result in decreased production of
endorphins Endorphins (contracted from endogenous morphine) are peptides produced in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in the pituitary gland of the brain. Endorphins are endogeno ...
in the brain, natural pain relievers whose effects may be heightened by drugs.
Cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...
alters one's state of consciousness. Cocaine affects the neurotransmitters that nerves use to communicate with each other. Cocaine inhibits the reuptake of
norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic compound, organic chemical in the catecholamine family that functions in the brain and human body, body as a hormone, neurotransmitter and neuromodulator. The ...
,
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, ...
,
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 ...
, and other
neurotransmitters A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, or target cell, may be another neuron, but could also be a gland or muscle cell. Neurotransmitters are rele ...
in the synapse, resulting in an altered state of consciousness or a "high" (Aldridge, D., & Fachner, J. ö. 2005). Lysergic acid diethylamide, or
LSD Lysergic acid diethylamide, commonly known as LSD (from German ; often referred to as acid or lucy), is a semisynthetic, hallucinogenic compound derived from ergot, known for its powerful psychological effects and serotonergic activity. I ...
, activates serotonin receptors (the amine transmitter of nerve urges) in brain matter. LSD acts on certain serotonin receptors, and its effects are most prominent in the
cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...
, an area involved in attitude, thought, and insight, which obtains sensory signs from all parts of the body. LSD's main effects are emotional and psychological. The ingester's feelings may alter quickly through a range from fear to
ecstasy Ecstasy most often refers to: * Ecstasy (emotion), a trance or trance-like state in which a person transcends normal consciousness * Religious ecstasy, a state of consciousness, visions or absolute euphoria * Ecstasy (philosophy), to be or stand o ...
(Humphrey, N. 2001). This may cause one to experience many levels of altered consciousness. It has also been shown to induce
ego death Ego death is a "complete loss of subjective self-identity". The term is used in various intertwined contexts, with related meanings. The 19th-century philosopher and psychologist William James uses the synonymous term "self-surrender", and Jung ...
(or ''ego dissolution'').
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 ...
alters consciousness by shifting levels of neurotransmitters. Neurotransmitters are endogenous chemicals that transmit signals across a synapse from one neuron (nerve cell) to another "target" cell (often another neuron). Neurotransmitters can cause inhibitory or excitatory effects on the "target" cell they are affecting. Alcohol increases the effect of the neurotransmitter GABA (
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 ...
) in the brain. GABA causes slow actions and inaudible verbal communication that often occur in alcoholics. Alcohol also decreases the excitatory neurotransmitter glutamate. Suppressing this stimulant results in a similar type of physiological slowdown. In addition to increasing the GABA and decreasing the glutamate in the brain, alcohol increases the amount of the chemical dopamine in the brain, which is one of the addictive causes of alcoholism.


Non-pharmacological

Altered states of consciousness may also be induced by: *
Hypnosis Hypnosis is a human condition involving focused attention (the selective attention/selective inattention hypothesis, SASI), reduced peripheral awareness, and an enhanced capacity to respond to suggestion.In 2015, the American Psychological ...
*
Meditation Meditation is a practice in which an individual uses a technique to train attention and awareness and detach from reflexive, "discursive thinking", achieving a mentally clear and emotionally calm and stable state, while not judging the meditat ...
*
Near-death experience A near-death experience (NDE) is a profound personal experience associated with death or impending death, which researchers describe as having similar characteristics. When positive, which the great majority are, such experiences may encompa ...
Emotions influence behavior that alters the state of consciousness. Emotions can be influenced by various stimuli.


Pathologies/other

Pathological or accidental induction may refer to unforeseen events or illnesses. According to Jeffrey R. Avner, professor of clinical pediatrics, a crucial element to understanding accidental and pathological causes of altered states of consciousness (ASCs) is that it begins with reduced self-awareness followed by reduced awareness in the environment (2006). Those with personal experience of conditions such as Depersonalisation often cite the opposite, that it is an increased awareness of the environment and the self that results in altered states of consciousness. When the reduction of self-awareness and environmental awareness take effect, they produce altered states of consciousness. The specific conditions below provide clarity on the types of conditions compromise accidental and pathological causes.


Traumatic experience

The first condition, traumatic experience, is defined as a lesion caused by an external force (Trauma. (n.d.) In Merriam-Webster Dictionary online, 2013). Examples include impact to the brain caused by blunt force (i.e., a car accident). The reason a traumatic experience causes altered states of consciousness is that it changes how the brain works. The external impact diverts the blood flow from the front of the brain to other areas. The front of the brain is known as the prefrontal cortex responsible for analytical thought (Kunsman, 2012). When the damage becomes uncontrollable, the patient experiences changes in behavior and impaired self-awareness. This is exactly when an altered state of consciousness is experienced.


Epilepsy

Another common cause of ASCs is
epilepsy Epilepsy is a group of Non-communicable disease, non-communicable Neurological disorder, neurological disorders characterized by a tendency for recurrent, unprovoked Seizure, seizures. A seizure is a sudden burst of abnormal electrical activit ...
. According to
Medlineplus MedlinePlus is an online information service produced by the United States National Library of Medicine. The service provides curated consumer health information in English and Spanish with select content in additional languages. The site brings ...
epilepsy is as a brain disorder that causes seizures (2013). During the seizure, the patient will experience hallucinations and loss of mental control, causing temporary dissociation from reality. A study that was conducted with six epileptic patients and used functional magnetic resonance imaging (fMRI) detected how the patients did indeed experience hallucinations while a seizure is occurring. This not only altered the patient's behavioral pattern but also made them dissociate from reality during that particular time frame.


Oxygen deficiency

Oxygen deficiency Hypoxia is a condition in which the body or a region of the body is deprived of an adequate oxygen supply at the tissue level. Hypoxia may be classified as either '' generalized'', affecting the whole body, or ''local'', affecting a region of t ...
impacts the brain, which is why ASCs can occur when there is oxygen deprivation in an environment.


Infections

In addition to oxygen deprivation or deficiency,
infections An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...
are a common pathological cause of ASC. A prime example of an infection is
meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...
. The medical website WEBMD states that meningitis is an infection that causes the coverings of the brain to swell. This particular infection occurs in children and young adults. This infection is primarily viral. Viral meningitis causes ASC and its symptoms include fevers and seizures (2010). The Impairment becomes visible the moment seizures begin to occur, this is when the patient enters the altered state of consciousness.


Sleep deprivation

Sleep deprivation Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either Chronic (medicine), chronic ...
is also associated with ASCs, and can provoke seizures due to fatigue. Sleep deprivation can be chronic or short-term depending on the severity of the patient's condition. Many patients report hallucinations because sleep deprivation impacts the brain. An
MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...
study conducted at Harvard Medical School in 2007 found that a sleep-deprived brain was not capable of being in control of its sensorimotor functions, leading to impaired self-awareness. Patients were also much clumsier than if they had not been experiencing sleep deprivation.


Fasting

Fasting Fasting is the act of refraining from eating, and sometimes drinking. However, from a purely physiological context, "fasting" may refer to the metabolic status of a person who has not eaten overnight (before "breakfast"), or to the metabolic sta ...
is another form of deprivation. Fasting can be deliberate, including for religious reasons or from psychological conditions such as
anorexia Anorexia nervosa (AN), often referred to simply as anorexia, is an eating disorder characterized by Calorie restriction, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. Individuals wit ...
. Fasting refers to the ability to willingly refrain from food and possibly drinks as well. The dissociation caused by fasting is not only life-threatening but it is the reason why extended fasting periods can lead to ASC. Thus, the temporary dissociation from reality allows fasting to fall into the category of an ASC following the definition provided by Avner (2006).


Psychosis

Another pathological cause is
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 ...
, otherwise known as a psychotic episode. Psychotic episodes often include
delusion A delusion is a fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some other m ...
s,
paranoia Paranoia is an instinct or thought process that is believed to be heavily influenced by anxiety, suspicion, or fear, often to the point of delusion and irrationality. Paranoid thinking typically includes persecutory beliefs, or beliefs of co ...
,
derealization Derealization is an alteration in the perception of the external world, causing those with the condition to perceive it as unreal, distant, distorted, or in other ways falsified. Other symptoms include feeling as if one's environment lacks spontan ...
,
depersonalization Depersonalization is a dissociative phenomenon characterized by a subjective feeling of detachment from oneself, manifesting as a sense of disconnection from one's thoughts, emotions, sensations, or actions, and often accompanied by a feeling of ...
, and
hallucination A hallucination is a perception in the absence of an external stimulus that has the compelling sense of reality. They are distinguishable from several related phenomena, such as dreaming ( REM sleep), which does not involve wakefulness; pse ...
s (Revonsuo et al., 2008). Studies have not been able to clearly identify when a person is reaching a higher level of risk for a psychotic episode (Schimmelmann, B., Walger, P., & Schultze-Lutter, F., 2013), but the earlier people are treated for psychosis the more likely they are to avoid the devastating consequences which could lead to a psychotic disorder (Schimmelmann, B., Walger, P., & Schultze-Lutter, F., 2013). Unfortunately, there are very few studies which have thoroughly investigated psychotic episodes, and the ability to predict this disorder remains unclear. (Schimmelmann, B., Walger, P., & Schultze-Lutter, F., 2013). Reviewing the previous conditions for accidental and pathological causes, we can come to understand that all of these accidental or pathological causes share the component of reduced
self-awareness In philosophy of self, philosophy, self-awareness is the awareness and reflection of one's own personality or individuality, including traits, feelings, and behaviors. It is not to be confused with consciousness in the sense of qualia. While ...
. Therefore, ASCs cannot only be caused naturally but they can be induced intentionally with methods including hypnosis meditation, amongst others. There are also ASCs which are caused by less recreational purposes; people who utilize illegal substances, or heavy dosages of medications, as well as large amounts of alcohol, can indeed comply with the definition of an ASC (Revonsuo et al., 2008).


Neurobiological models of altered state experiences


Entropic brain hypothesis

The entropic brain hypothesis by Robin Carhart-Harris in 2014 is a theory informed by neuroimaging research that uses the hallucinogen-induced neurological state to make inferences about other states of consciousness. The expression "entropy" is applied here in the context of states of consciousness and their associated
neurodynamics Neural oscillations, or brainwaves, are rhythmic or repetitive patterns of neural activity in the central nervous system. Neural tissue can generate oscillatory activity in many ways, driven either by mechanisms within individual neurons or by ...
, where high entropy means a high level of disorder. The theory proposes a general distinction between two fundamentally different modes of cognition, referred to as primary and secondary consciousness. Primary consciousness is associated with unconstrained cognition and less ordered (higher-entropy) neurodynamics that preceded the development of modern, normal waking consciousness in adults. Examples include the rapid eye movement sleep (REM),transcendental state between REM sleep and sensory awareness(the psychedelic state), or the onset phase of
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 ...
. Secondary consciousness is associated with constrained cognition and more ordered neurodynamics. Examples include normal waking consciousness, the anesthetized or the depressed state. The theory further proposes that via pharmacological induction of psychedelic substances
psilocybin Psilocybin, also known as 4-phosphoryloxy-''N'',''N''-dimethyltryptamine (4-PO-DMT), is a natural product, naturally occurring tryptamine alkaloid and Investigational New Drug, investigational drug found in more than List of psilocybin mushroom ...
, the brain is able to enter into the primary state of consciousness (the psychedelic state) from normal waking consciousness. This "phase transition" between these two fundamentally different poles of consciousness is facilitated by a collapse of the normally highly organized activity within the
default mode network In neuroscience, the default mode network (DMN), also known as the default network, default state network, or anatomically the medial frontoparietal network (M-FPN), is a large-scale brain network primarily composed of the dorsal medial prefro ...
(DMN) and a decoupling between the DMN and the medial
temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved in pr ...
s (MTLs), which are normally significantly coupled. The DMN is closely associated with higher-order cognitive functions such as supporting the neurological basis for the self (e.g. self-reflection, subjectivity, introspection), thinking about others (e.g.
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 ...
), remembering the past and thinking about the future (e.g.
episodic memory Episodic memory is the memory of everyday events (such as times, location geography, associated emotions, and other contextual information) that can be explicitly stated or conjured. It is the collection of past personal experiences that occurred ...
). Task-positive networks are associated with the inverse of these things e.g., focus on and scrutiny of the external world. The entropic brain hypothesis emphasizes the great research potential of the psychedelic state of mind for gaining more insight into general human consciousness.


CSTC-loop

Extensive scientific investigation on altered states of consciousness and their relationship to drug interactions with receptors in the brain have been performed. Particularly the study of 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 ...
serotonin and the effects of psychedelic drugs on the brain has been intensively researched over the past sixty years. It has been hypothesized that hallucinogens act either as an
antagonist An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.agonist An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...
at 5-HT2A (serotonin-2A) receptors and will elicit a state that shares some common phenomenological features with early acute stages of the group of schizophrenia disorders. Findings implicate that abnormalities of serotonin function and the serotonergic system could be responsible for psychiatric disorders such as the spectrum of schizophrenia (gating) disorders and therefore, that serotonin agonist or antagonists might be useful in the treatment of 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 ...
. To investigate the underlying causative neurotransmitter mechanisms of this phenomenon, the CSTC (cortico-striato-thalamo-cortical) loop model has been formulated based on empirical neurobiological work. It is indicated that the common hypofrontality (underactivation of frontal brain regions) and cortical activation pattern induced by
serotonergic A serotonergic substance, medication, or receptor protein is one that affects neurotransmission pathways that involve serotonin, as follows: * Serotonergic drugs ** Serotonin receptor agonists ** Serotonin receptor antagonists ** Serotonin reupta ...
and
glutamatergic Glutamatergic means "related to glutamate". A glutamatergic agent (or drug) is a chemical that directly modulates the excitatory amino acid (glutamate/aspartate) system in the body or brain. Examples include excitatory amino acid receptor agonist ...
hallucinogens is due to a common disruption of
thalamic The thalamus (: thalami; from Greek θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the ...
gating of sensory and cognitive information. The CSTC feedback loop plays a major role in gating or filtering out external and internal information to the cortex. Thereby it influences the regulation of the level of awareness and attention. Disruption of the CSTC loop system is proposed to significantly influence information processing, for instance the ability to screen out, inhibit, filter, or gate extraneous stimuli and to direct selective attention to salient features of the environment. Failures of these attentional gating mechanisms might overload patients with the excessive processing of both sensory and cognitive stimuli, which could lead to a breakdown of cognitive integrity and difficulty in distinguishing self from non-self and failure to integrate an overwhelming flood of information. Descriptive elaboration of the mentioned effects can be found in the literature on schizophrenia as well as in descriptions of hallucinogenic drug action. Despite strong evidence linking serotonin and psychosis, novel research indicates that some behavioral effects of drugs such as psilocybin appear to be independent of the classical 5-HT2A receptor-agonist actions, implying that the model described here is not the only underlying framework at play. Interdisciplinary research enterprises have set out to study the convergence of serotonergic and glutamatergic models of psychosis and dynamic neurotransmitter interactions, derived from the study of hallucinogenic drugs, in the future.


Synthetic surprise

Synthetic surprise is a theoretical concept explaining the altered states of consciousness induced by psychedelic substances like LSD and psilocybin. Central to this concept is the activation of the 5-HT2A receptor by psychedelics. The hypothesis suggests that these substances induce a state of synthetic surprise through the selective activation of the 5-HT receptors system, based on recent insights supporting a role of 5-HT in signaling surprise. This state aligns with the 'prediction error' in the predictive coding framework of brain function, where there's a discrepancy between the brain's expectations and the actual sensory input. The precision of this sensory data is crucial in modifying the brain's pre-existing beliefs or 'priors'. Under the influence of psychedelics, the interplay between top-down expectations and bottom-up sensory information is altered, leading to the characteristic changes in consciousness. Hallucinations in this context can be explained by the previously proposed "Strong priors" theory. This understanding of synthetic surprise has significant implications for the clinical use of psychedelic substances. The ability of psychedelics to induce surprise is proposed to be central to their therapeutic potential, especially in disrupting maladaptive cognitive and perceptual patterns.


See also

*
Absorption (psychology) Absorption is a disposition or personality trait in which a person becomes absorbed in their mental imagery, particularly fantasy. This trait thus correlates highly with a fantasy prone personality. The original research on absorption was by Dutc ...
*
Delirium Delirium (formerly acute confusional state, an ambiguous term that is now discouraged) is a specific state of acute confusion attributable to the direct physiological consequence of a medical condition, effects of a psychoactive substance, or ...
*
Flow (psychology) Flow in positive psychology, also known colloquially as being in the zone or locked in, is the mental state in which a person performing some activity is fully immersed in a feeling of energized Attention, focus, full involvement, and enjoyment ...
*
Hydrogen narcosis Hydrogen narcosis (also known as the hydrogen effect – a rather ambiguous term) is the psychotropic state induced by breathing hydrogen at high partial pressures. Hydrogen narcosis produces symptoms such as hallucinations, disorientation, and co ...
*
Lucid dreaming In the psychology subfield of oneirology, a lucid dream is a type of dream wherein the dreamer realizes that they are dreaming during their dream. The capacity to have lucid dreams is a trainable cognitive skill. During a lucid dream, the dreamer ...
* Night of Pan *
Psychonautics Psychonautics (from the Ancient Greek ' 'soul, spirit, mind' and ' 'sailor, navigator') refers both to a methodology for describing and explaining the subjective effects of altered states of consciousness, including those induced by meditatio ...
* Runner's high *
Sensory deprivation Sensory deprivation or perceptual isolation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing, while more complex devices can ...
*
Trance Trance is a state of semi-consciousness in which a person is not self-aware and is either altogether unresponsive to external stimuli (but nevertheless capable of pursuing and realizing an aim) or is selectively responsive in following the dir ...


Notes


References


Sources

* "Harvard Heart Letter examines the costs of not getting enough sleep – Harvard Health Publications". Health.harvard.edu. 31 May 2012. Retrieved 2012-08-13. * Aldridge, D., & Fachner, J. ö. (2005). Chapter 7: Music and drug-induced altered states of consciousness. (pp. 82–96) * * * * * * * * * * * Louis Breger. (1967) Function of Dreams. ''Journal of Abnormal Psychology Monograph'', Vol 72, No. 5, Part 2 of 2 Parts, 1–28 * Meningitis - Topic Overview (December 8, 2010) from
Meningitis (Bacterial, Viral, and Fungal)
* * * * *


Further reading

* Beyerstein, Barry. "Altered States of Consciousness," in The Encyclopedia of the Paranormal, edited by Gordon Stein (Buffalo, N.Y.: Prometheus Books, 1996). * Beyerstein, Barry. "The Myth of Alpha Consciousness", Skeptical Inquirer, 10, no. 1
985 Year 985 ( CMLXXXV) was a common year starting on Thursday of the Julian calendar. Events By place Europe * Summer – Henry II (the Wrangler) is restored as duke of Bavaria by Empress Theophanu and her mother-in-law Adelaide at an ...
* Blackmore, Susan J., Dying to Live : Near-death Experiences, (Buffalo, N.Y.: Prometheus Books, 1993). * Bourguignon, Erika (1973). ''Religion, Altered States of Consciousness, and Social Change.'' Ohio State Univ. Press, Columbus.
Full text
* * James, William (1902). ''The Varieties of Religious Experience'' * * Persinger, Michael. Neuropsychological Bases of God Beliefs (Praeger Pub Text., 1987). *Roberts, T.B. "Chemical Input—Religious Output: Entheogens." Chapter 10 of ''Where God and Science Meet: Vol. 3: The Psychology of Religious Experience''. Edited by Robert McNamara. Westport, CT: Praeger/Greenwood, 2006. *Roberts, T.B. (Ed.) (2001). ''Psychoactive Sacramentals: Essays on Entheogens and Religion.'' San Francisco:
Council on Spiritual Practices Psychedelic therapy (or psychedelic-assisted therapy) refers to the proposed use of psychedelic drugs, such as psilocybin, ayahuasca, LSD, psilocin, mescaline (peyote), DMT, 5-MeO-DMT, Ibogaine, MDMA, to treat mental disorders. As of 2021, psyche ...
. *Roberts, T.B. and P.J. Hruby. (1995–2002). ''Religion and Psychoactive Sacraments: An Entheogen Chrestomathy ''. Online archive *Shear, Jonathan. (2011). "Eastern Approaches to Altered States of Consciousness". Altering consciousness. volume 1: multidisciplinary perspectives. *Wier, Dennis R. (1995) ''Trance: From Magic to Technology''. Transmedia. {{DEFAULTSORT:Altered state of consciousness Consciousness Hallucinations Hypnosis Mysticism Neuroscience Mental states Perception