Dissociation (psychology)Dissociation is a concept that has been developed over time and which concerns a wide array of experiences, ranging from a mild emotional detachment from the immediate surroundings, to a more severe disconnection from physical and emotional experiences. The major characteristic of all dissociative phenomena involves a detachment from reality, rather than a loss of reality as in psychosis. The phenomena are diagnosable under the DSM-5 as a group of disorders as well as a symptom of other disorders through various diagnostic tools.
Dissociative identity disorderDissociative identity disorder (DID), formerly known as multiple personality disorder, split personality disorder or dissociative personality disorder, is a member of the family of dissociative disorders classified by the DSM-5, DSM-5-TR, ICD-10, ICD-11, and Merck Manual for diagnosis. It remains a controversial diagnosis, despite rigorous study in the scientific literature since 1975. Dissociative identity disorder is characterized by the presence of at least two distinct and relatively enduring personality states.
Schizotypal personality disorderSchizotypal personality disorder (StPD or SPD), also known as schizotypal disorder, is a cluster A personality disorder. The Diagnostic and Statistical Manual of Mental Disorders (DSM) classification describes the disorder specifically as a personality disorder characterized by thought disorder, paranoia, a characteristic form of social anxiety, derealization, transient psychosis, and unconventional beliefs.
ElectroencephalographyElectroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with the EEG electrodes placed along the scalp (commonly called "scalp EEG") using the International 10–20 system, or variations of it. Electrocorticography, involving surgical placement of electrodes, is sometimes called "intracranial EEG".
DissociativeDissociatives, colloquially dissos, are a subclass of hallucinogens which distort perception of sight and sound and produce feelings of detachment – dissociation – from the environment and/or self. Although many kinds of drugs are capable of such action, dissociatives are unique in that they do so in such a way that they produce hallucinogenic effects, which may include dissociation, a general decrease in sensory experience, hallucinations, dream-like states or anesthesia.
Depersonalization-derealization disorderDepersonalization-derealization disorder (DPDR, DPD) is a mental disorder in which the person has persistent or recurrent feelings of depersonalization and/or derealization. Depersonalization is described as feeling disconnected or detached from one's self. Individuals may report feeling as if they are an outside observer of their own thoughts or body, and often report feeling a loss of control over their thoughts or actions. Derealization is described as detachment from one's surroundings.
Dissociative fugueDissociative fugue (fjuːɡ), formerly called a fugue state or psychogenic fugue, is a mental and behavioral disorder that is classified variously as a dissociative disorder, a conversion disorder, and a somatic symptom disorder. The disorder is a rare psychiatric phenomenon characterized by reversible amnesia for one's identity, including the memories, personality, and other identifying characteristics of individuality. The state can last for days, months, or longer.
SchizotypyIn psychology, schizotypy is a theoretical concept that posits a continuum of personality characteristics and experiences, ranging from normal dissociative, imaginative states to extreme states of mind related to psychosis, especially schizophrenia. The continuum of personality proposed in schizotypy is in contrast to a categorical view of psychosis, wherein psychosis is considered a particular (usually pathological) state of mind, which the person either has or does not have.
Guided imageryGuided imagery (also known as guided affective imagery, or katathym-imaginative psychotherapy) is a mind-body intervention by which a trained practitioner or teacher helps a participant or patient to evoke and generate s that simulate or recreate the sensory perception of sights, sounds, tastes, smells, movements, and images associated with touch, such as texture, temperature, and pressure, as well as imaginative or mental content that the participant or patient experiences as defying conventional sensory ca
SchizophreniaSchizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdrawal, and flat affect. Symptoms typically develop gradually, begin during young adulthood, and in many cases never become resolved. There is no objective diagnostic test; diagnosis is based on observed behavior, a psychiatric history that includes the person's reported experiences, and reports of others familiar with the person.
Functional neuroimagingFunctional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions. It is primarily used as a research tool in cognitive neuroscience, cognitive psychology, neuropsychology, and social neuroscience.
Near-death experienceA 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 encompass a variety of sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, joy, the experience of absolute dissolution, review of major life events, the presence of a light, and seeing dead relatives.
Hallucinogen persisting perception disorderHallucinogen persisting perception disorder (HPPD) is a non-psychotic disorder in which a person experiences apparent lasting or persistent visual hallucinations or perceptual distortions after a previous use of drugs, including but not limited to psychedelics, dissociatives, entactogens, tetrahydrocannabinol (THC), and SSRIs. Despite being designated as a hallucinogen-specific disorder, the specific contributory role of psychedelic drugs is unknown.
ElectrocorticographyElectrocorticography (ECoG), a type of intracranial electroencephalography (iEEG), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery (intraoperative ECoG) or outside of surgery (extraoperative ECoG).
Mental imageIn philosophy of mind, neuroscience, and cognitive science, a mental image is an experience that, on most occasions, significantly resembles the experience of "perceiving" some object, event, or scene, but occurs when the relevant object, event, or scene is not actually present to the senses. There are sometimes episodes, particularly on falling asleep (hypnagogic imagery) and waking up (hypnopompic imagery), when the mental imagery may be dynamic, phantasmagoric and involuntary in character, repeatedly presenting identifiable objects or actions, spilling over from waking events, or defying perception, presenting a kaleidoscopic field, in which no distinct object can be discerned.
NeuroimagingNeuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Increasingly it is also being used for quantitative research studies of brain disease and psychiatric illness. Neuroimaging is highly multidisciplinary involving neuroscience, computer science, psychology and statistics, and is not a medical specialty.
SynesthesiaSynesthesia (American English) or synaesthesia (British English) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second sensory or cognitive pathway. People who report a lifelong history of such experiences are known as synesthetes. Awareness of synesthetic perceptions varies from person to person. In one common form of synesthesia, known as grapheme–color synesthesia or color–graphemic synesthesia, letters or numbers are perceived as inherently colored.
Spectrum disorderA spectrum disorder is a mental 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 the same underlying mechanism. In either case, a spectrum approach is taken because there appears to be "not a unitary disorder but rather a syndrome composed of subgroups". The spectrum may represent a range of severity, comprising relatively "severe" mental disorders through to relatively "mild and nonclinical deficits".
Development of the nervous system in humansThe development of the nervous system in humans, or neural development or neurodevelopment involves the studies of embryology, developmental biology, and neuroscience to describe the cellular and molecular mechanisms by which the complex nervous system forms in humans, develops during prenatal development, and continues to develop postnatally.
HallucinogenHallucinogens are a large and diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, mood, and perception as well as other changes. Most hallucinogens can be categorized as either being psychedelics, dissociatives, or deliriants. The word hallucinogen is derived from the word hallucination. The term hallucinate dates back to around 1595–1605, and is derived from the Latin hallūcinātus, the past participle of (h)allūcināri, meaning "to wander in the mind.
