What is Dissociative Disorder?

Introduction

Dissociative disorders (DD) are conditions that involve disruptions or breakdowns of memory, awareness, identity, or perception.

People with dissociative disorders use dissociation as a defence mechanism, pathologically and involuntarily. The individual experiences these dissociations to protect themselves. Some dissociative disorders are triggered by psychological trauma, but depersonalisationderealisation disorder may be preceded only by stress, psychoactive substances, or no identifiable trigger at all.

The dissociative disorders listed in the American Psychiatric Association’s DSM-5 are as follows:

  • Dissociative identity disorder (formerly multiple personality disorder): the alternation of two or more distinct personality states with impaired recall among personality states. In extreme cases, the host personality is unaware of the other, alternating personalities; however, the alternate personalities can be aware of all the existing personalities.
  • Dissociative amnesia (formerly psychogenic amnesia): the temporary loss of recall memory, specifically episodic memory, due to a traumatic or stressful event. It is considered the most common dissociative disorder amongst those documented. This disorder can occur abruptly or gradually and may last minutes to years depending on the severity of the trauma and the patient. Dissociative fugue was previously a separate category but is now treated as a specifier for dissociative amnesia.
  • Depersonalisation-derealisation disorder: periods of detachment from self or surrounding which may be experienced as “unreal” (lacking in control of or “outside” self) while retaining awareness that this is only a feeling and not a reality.
  • The old category of dissociative disorder not otherwise specified is now split into two: other specified dissociative disorder, and unspecified dissociative disorder. These categories are used for forms of pathological dissociation that do not fully meet the criteria of the other specified dissociative disorders; or if the correct category has not been determined; or the disorder is transient.

The ICD 11 lists dissociative disorders as:

  • Dissociative neurological symptom disorder.
  • Dissociative amnesia.
  • Dissociative amnesia with dissociative fugue.
  • Trance disorder.
  • Possession trance disorder.
  • Dissociative identity disorder.
  • Partial dissociative identity disorder.
  • Depersonalisation-derealisation disorder.

Cause and Treatment

Dissociative Identity Disorder

Cause

Dissociative identity disorder is caused by ongoing childhood trauma that occurs before the ages of six to nine. People with dissociative identity disorder usually have close relatives who have also had similar experiences.

Treatment

Long-term psychotherapy to improve the patient’s quality of life.

Dissociative Amnesia

Cause

A way to cope with trauma.

Treatment

Psychotherapy (e.g. talk therapy) counselling or psychosocial therapy which involves talking about your disorder and related issues with a mental health provider. Psychotherapy often involves hypnosis (help you remember and work through the trauma); creative art therapy (using creative process to help a person who cannot express his or her thoughts); cognitive therapy (talk therapy to identify unhealthy and negative beliefs/behaviours); and medications (antidepressants, anti-anxiety medications, or sedatives). These medications help control the symptoms associated with the dissociative disorders, but there are no medications yet that specifically treat dissociative disorders. However, the medication pentothal can sometimes help to restore the memories. The length of an event of dissociative amnesia may be a few minutes or several years. If an episode is associated with a traumatic event, the amnesia may clear up when the person is removed from the traumatic situation. Dissociative fugue was a separate category but is now listed as a specifier for dissociative amnesia.

Depersonalisation-Derealisation Disorder

Cause

Dissociative disorders usually develop as a way to cope with trauma. The disorders most often form in children subjected to chronic physical, sexual or emotional abuse or, less frequently, a home environment that is otherwise frightening or highly unpredictable; however, this disorder can also acutely form due to severe traumas such as war or the death of a loved one.

Treatment

Same treatment as dissociative amnesia. An episode of depersonalisationderealisation disorder can be as brief as a few seconds or continue for several years.

Dissociative disorders, especially dissociative identity disorder (DID), while being the result of extraordinary abuse and trauma in childhood, it should not be attributed exotic status. DID would be better examined through a more holistic lens, taking into considering the social, cognitive, and neural components, and how they interact with one another.

Medications

There are no medications to treat dissociative disorders, however, drugs to treat anxiety and depression that may accompany the disorders can be given.

Diagnosis and Prevalence

The lifetime prevalence of dissociative disorders varies from 10% in the general population to 46% in psychiatric inpatients. Diagnosis can be made with the help of structured clinical interviews such as the Dissociative Disorders Interview Schedule (DDIS) and the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D-R), and behavioural observation of dissociative signs during the interview. Additional information can be helpful in diagnosis, including the Dissociative Experiences Scale or other questionnaires, performance-based measures, records from doctors or academic records, and information from partners, parents, or friends. A dissociative disorder cannot be ruled out in a single session and it is common for patients diagnosed with a dissociative disorder to not have a previous dissociative disorder diagnosis due to a lack of clinician training. Some diagnostic tests have also been adapted or developed for use with children and adolescents such as the Adolescent Dissociative Experiences Scale, Children’s Version of the Response Evaluation Measure (REM-Y-71), Child Interview for Subjective Dissociative Experiences, Child Dissociative Checklist (CDC), Child Behaviour Checklist (CBCL) Dissociation Subscale, and the Trauma Symptom Checklist for Children Dissociation Subscale.

Dissociative disorders have been found to be quite prevalent in outpatient populations, as well as within low-income communities. One study found that in a population of poor inner-city outpatients, there was a 29% prevalence of dissociative disorders.

There are problems with classification, diagnosis and therapeutic strategies of dissociative and conversion disorders which can be understood by the historic context of hysteria. Even current systems used to diagnose DD such as the DSM-IV and ICD-10 differ in the way the classification is determined. In most cases mental health professionals are still hesitant to diagnose patients with Dissociative Disorder, because before they are considered to be diagnosed with Dissociative Disorder these patients have more than likely been diagnosed with major depressive disorder, anxiety disorder, and most often post-traumatic stress disorder (PTSD). It has been found from interviews with those who may be afflicted with dissociative disorders may be more effective at getting an accurate diagnosis than self-scoring assessments and scales.

The prevalence of dissociative disorders is not completely understood due to the many difficulties in diagnosing dissociative disorders. Many of these difficulties stem from a misunderstanding of dissociative disorders, from an unfamiliarity diagnosis or symptoms to disbelief in some dissociative disorders entirely. Due to this it has been found that only 28% to 48% of people diagnosed with a dissociative disorder receive treatment for their mental health. Patients who are misdiagnosed are often those more likely to be hospitalised repeatedly, and lack of treatment can result in intensive outpatient treatment and higher rates of disability.

An important concern in the diagnosis of dissociative disorders in forensic interviews is the possibility that the patient may be feigning symptoms in order to escape negative consequences. Young criminal offenders report much higher levels of dissociative disorders, such as amnesia. In one study it was found that 1% of young offenders reported complete amnesia for a violent crime, while 19% claimed partial amnesia. There have also been cases in which people with dissociative identity disorder provide conflicting testimonies in court, depending on the personality that is present. The world-wide prevalence of dissociative disorders is not well understood due to different cultural beliefs surrounding human emotions and the human brain

Children and Adolescents

Dissociative disorders (DD) are widely believed to have roots in adverse childhood experiences including abuse and loss, but the symptoms often go unrecognised or are misdiagnosed in children and adolescents. However, a recent western Chinese study showed an increase in awareness of dissociative disorders present in children These studies show that DD’s have an intricate relationship with the patient’s mental, physical and socio-cultural environments. This study suggested that dissociative disorders are more common in Western, or developing countries, however, some cases have been seen in both clinical and non-clinical Chinese populations. There are several reasons why recognising symptoms of dissociation in children is challenging: it may be difficult for children to describe their internal experiences; caregivers may miss signals or attempt to conceal their own abusive or neglectful behaviours; symptoms can be subtle or fleeting; disturbances of memory, mood, or concentration associated with dissociation may be misinterpreted as symptoms of other disorders.

Another resource, Beacon House, informs us of dissociative disorder in children, suggesting that it is a survival mechanism that often goes unnoticed in children that have been traumatised. Dr. Shoshanah Lyons suggests that traumatised children often continue to dissociate even though they might not be in any danger, and that they are often unaware that they are dissociating. In addition to developing diagnostic tests for children and adolescents (see above), a number of approaches have been developed to improve recognition and understanding of dissociation in children. Recent research has focused on clarifying the neurological basis of symptoms associated with dissociation by studying neurochemical, functional and structural brain abnormalities that can result from childhood trauma. Others in the field have argued that recognising disorganised attachment (DA) in children can help alert clinicians to the possibility of dissociative disorders. In their 2008 article, Rebecca Seligman and Laurence Kirmayer suggest the existence of evidence of linkages between trauma experienced in childhood and the capacity for dissociation or depersonalisation. They also suggest that individuals who are able to utilise dissociative techniques are able to keep this as an extended strategy to cope with stressful situations.

Clinicians and researchers stress the importance of using a developmental model to understand both symptoms and the future course of DDs. In other words, symptoms of dissociation may manifest differently at different stages of child and adolescent development and individuals may be more or less susceptible to developing dissociative symptoms at different ages. Further research into the manifestation of dissociative symptoms and vulnerability throughout development is needed. Related to this developmental approach, more research is required to establish whether a young patient’s recovery will remain stable over time.

Current Debates and the DSM-5

A number of controversies surround DD in adults as well as children. First, there is ongoing debate surrounding the aetiology of dissociative identity disorder (DID). The crux of this debate is if DID is the result of childhood trauma and disorganized attachment. A proposed view is that dissociation has a physiological basis, in that it involves automatically triggered mechanisms such as increased blood pressure and alertness, that would, as Lynn contends, imply its existence as a cross-species disorder. A second area of controversy surrounds the question of whether or not dissociation as a defence versus pathological dissociation are qualitatively or quantitatively different. Experiences and symptoms of dissociation can range from the more mundane to those associated with PTSD or acute stress disorder (ASD) to dissociative disorders. Mirroring this complexity, the DSM-5 workgroup considered grouping dissociative disorders with other trauma/stress disorders, but instead decided to put them in the following chapter to emphasize the close relationship. The DSM-5 also introduced a dissociative subtype of PTSD.

A 2012 review article supports the hypothesis that current or recent trauma may affect an individual’s assessment of the more distant past, changing the experience of the past and resulting in dissociative states. However, experimental research in cognitive science continues to challenge claims concerning the validity of the dissociation construct, which is still based on Janetian notions of structural dissociation. Even the claimed etiological link between trauma/abuse and dissociation has been questioned. Links observed between trauma/abuse and DD are largely only present from a Western cultural context. For non-Western cultures dissociation “may constitute a “normal” psychological capacity”. An alternative model proposes a perspective on dissociation based on a recently established link between a labile sleep-wake cycle and memory errors, cognitive failures, problems in attentional control, and difficulties in distinguishing fantasy from reality.

Debates around DD also stem from Western versus non-Western lenses of viewing the disorder, and associated views of causes of DD. DID was initially believed to be specific to the West, until cross-cultural studies indicated its occurrence worldwide. Conversely, anthropologists have largely done little work on DD in the West relating to its perceptions of possession syndromes that would be present in non-Western societies. While dissociation has been viewed and catalogued by anthropologists differently in the West and non-Western societies, there are aspects of each that show DD has universal characteristics. For example, while shamanic and rituals of non-Western societies may hold dissociative aspects, this is not exclusive as many Christian sects, such as “possession by the Holy Ghost” share similar qualities to those of non-Western trances.

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What is Dissociative Disorder Not Otherwise Specified?

Introduction

Dissociative disorder not otherwise specified (DDNOS) is a mental health diagnosis for pathological dissociation that matches the DSM-5 criteria for a dissociative disorder, but does not fit the full criteria for any of the specifically identified subtypes, which include dissociative identity disorder, dissociative amnesia, and depersonalisation/derealisation disorder, and the reasons why the previous diagnoses were not met are specified.

Refer to Depressive Disorder Not Otherwise Specified (DD-NOS).

Background

“Unspecified dissociative disorder” is given when the clinician does not give a reason. The International Statistical Classification of Diseases and Related Health Problems (ICD-10) refers to the diagnosis as “Other dissociative and conversion disorders”.

Examples of DDNOS include chronic and recurrent syndromes of mixed dissociative symptoms, identity disturbance due to prolonged and intense coercive persuasion, disorders similar to dissociative identity disorder, acute dissociative reactions to stressful events, and dissociative trance.

DDNOS is the most common dissociative disorder and is diagnosed in 40% of dissociative disorder cases. It is often co-morbid with other mental illnesses such as complex posttraumatic stress disorder, major depressive disorder, generalised anxiety disorder, personality disorders, substance use disorders, and eating disorders.

What is Depersonalisation?

Introduction

Depersonalisation can consist of a detachment within the self, regarding one’s mind or body, or being a detached observer of oneself.

Subjects feel they have changed and that the world has become vague, dreamlike, less real, lacking in significance or being outside reality while looking in. Chronic depersonalisation refers to depersonalisation/derealisation disorder, which is classified by the DSM-5 as a dissociative disorder, based on the findings that depersonalisation and derealisation are prevalent in other dissociative disorders including dissociative identity disorder.

Though degrees of depersonalisation and derealisation can happen to anyone who is subject to temporary anxiety or stress, chronic depersonalisation is more related to individuals who have experienced a severe trauma or prolonged stress/anxiety. Depersonalisation-derealisation is the single most important symptom in the spectrum of dissociative disorders, including dissociative identity disorder and “dissociative disorder not otherwise specified” (DD-NOS). It is also a prominent symptom in some other non-dissociative disorders, such as anxiety disorders, clinical depression, bipolar disorder, schizophrenia, schizoid personality disorder, hypothyroidism or endocrine disorders, schizotypal personality disorder, borderline personality disorder, obsessive compulsive disorder, migraines, and sleep deprivation; it can also be a symptom of some types of neurological seizure.

In social psychology, and in particular self-categorisation theory, the term depersonalisation has a different meaning and refers to “the stereotypical perception of the self as an example of some defining social category”.

Description

Individuals who experience depersonalisation feel divorced from their own personal self by sensing their body sensations, feelings, emotions, behaviours etc. as not belonging to the same person or identity. Often a person who has experienced depersonalisation claims that things seem unreal or hazy. Also, a recognition of a self breaks down (hence the name). Depersonalisation can result in very high anxiety levels, which further increase these perceptions.

Depersonalisation is a subjective experience of unreality in one’s self, while derealisation is unreality of the outside world. Although most authors currently regard depersonalisation (self) and derealisation (surroundings) as independent constructs, many do not want to separate derealisation from depersonalisation.

Prevalence

Depersonalisation is a symptom of anxiety disorders, such as panic disorder. It can also accompany sleep deprivation (often occurring when suffering from jet lag), migraine, epilepsy (especially temporal lobe epilepsy, complex-partial seizure, both as part of the aura and during the seizure), obsessive compulsive disorder, severe stress or trauma, anxiety, the use of recreational drugs – especially cannabis, hallucinogens, ketamine, and MDMA, certain types of meditation, deep hypnosis, extended mirror or crystal gazing, sensory deprivation, and mild-to-moderate head injury with little or full loss of consciousness (less likely if unconscious for more than 30 mins). Interoceptive exposure is a non-pharmacological method that can be used to induce depersonalisation.

In the general population, transient depersonalisation/derealisation are common, having a lifetime prevalence between 26-74%. A random community-based survey of 1,000 adults in the US rural south found a 1-year depersonalisation prevalence rate at 19%. Several studies, but not all, found age to be a significant factor: adolescents and young adults in the normal population reported the highest rate. In a study, 46% of college students reported at least one significant episode in the previous year. In another study, 20% of patients with minor head injury experience significant depersonalisation and derealisation. Several studies found that up to 66% of individuals in life-threatening accidents report transient depersonalisation at minimum during or immediately after the accidents. Depersonalisation occurs 2-4 times more in women than in men.

A similar and overlapping concept called ipseity disturbance (ipse is Latin for “self” or “itself”) may be part of the core process of schizophrenia spectrum disorders. However, specific to the schizophrenia spectrum seems to be “a dislocation of first-person perspective such that self and other or self and world may seem to be non-distinguishable, or in which the individual self or field of consciousness takes on an inordinate significance in relation to the objective or intersubjective world” (emphasis in original).

For the purposes of evaluation and measurement depersonalisation can be conceived of as a construct and scales are now available to map its dimensions in time and space. A study of undergraduate students found that individuals high on the depersonalisation/derealisation subscale of the Dissociative Experiences Scale exhibited a more pronounced cortisol response in stress. Individuals high on the absorption subscale, which measures a subject’s experiences of concentration to the exclusion of awareness of other events, showed weaker cortisol responses.

In general infantry and special forces soldiers, measures of depersonalisation and derealisation increased significantly after training that includes experiences of uncontrollable stress, semi-starvation, sleep deprivation, as well as lack of control over hygiene, movement, communications, and social interactions.

Pharmacological and Situational Causes

Depersonalisation has been described by some as a desirable state, particularly by those that have experienced it under the influence of mood-altering recreational drugs. It is an effect of dissociatives and psychedelics, as well as a possible side effect of caffeine, alcohol, amphetamine, cannabis, and antidepressants. It is a classic withdrawal symptom from many drugs.

Benzodiazepine dependence, which can occur with long-term use of benzodiazepines, can induce chronic depersonalisation symptomatology and perceptual disturbances in some people, even in those who are taking a stable daily dosage, and it can also become a protracted feature of the benzodiazepine withdrawal syndrome.

Lieutenant Colonel Dave Grossman, in his book On Killing, suggests that military training artificially creates depersonalisation in soldiers, suppressing empathy and making it easier for them to kill other human beings.

Graham Reed (1974) claimed that depersonalisation occurs in relation to the experience of falling in love.

Depersonalisation as a Psychobiological Mechanism

Depersonalisation is a classic response to acute trauma, and may be highly prevalent in individuals involved in different traumatic situations including motor vehicle accident, and imprisonment.

Psychologically depersonalisation can, just like dissociation in general, be considered a type of coping mechanism. Depersonalisation is in that case unconsciously used to decrease the intensity of unpleasant experience, whether that is something as mild as stress or something as severe as chronically high anxiety and post-traumatic stress disorder. The decrease in anxiety and psychobiological hyperarousal helps preserving adaptive behaviours and resources under threat or danger. Depersonalisation is an overgeneralised reaction in that it does not diminish just the unpleasant experience, but more or less all experience – leading to a feeling of being detached from the world and experiencing it in a more bland way. An important distinction must be made between depersonalisation as a mild, short term reaction to unpleasant experience and depersonalisation as a chronic symptom stemming from a severe mental disorder such as PTSD or Dissociative Identity Disorder. Chronic symptoms may represent persistence of depersonalization beyond the situations under threat.

Treatment

Treatment is dependent on the underlying cause, whether it is organic or psychological in origin. If depersonalisation is a symptom of neurological disease, then diagnosis and treatment of the specific disease is the first approach. Depersonalisation can be a cognitive symptom of such diseases as amyotrophic lateral sclerosis, Alzheimer’s, multiple sclerosis (MS), or any other neurological disease affecting the brain. For those suffering from depersonalisation with migraine, tricyclic antidepressants are often prescribed.

If depersonalization is a symptom of psychological causes such as developmental trauma, treatment depends on the diagnosis. In case of dissociative identity disorder or DD-NOS as a developmental disorder, in which extreme developmental trauma interferes with formation of a single cohesive identity, treatment requires proper psychotherapy, and – in the case of additional (co-morbid) disorders such as eating disorders – a team of specialists treating such an individual. It can also be a symptom of borderline personality disorder, which can be treated in the long term with proper psychotherapy and psychopharmacology.

The treatment of chronic depersonalisation is considered in depersonalisation disorder.

A recently completed study at Columbia University in New York City has shown positive effects from transcranial magnetic stimulation (TMS) to treat depersonalisation disorder. Currently, however, the FDA has not approved TMS to treat DP.

A 2001 Russian study showed that naloxone, a drug used to reverse the intoxicating effects of opioid drugs, can successfully treat depersonalization disorder. According to the study: “In three of 14 patients, depersonalization symptoms disappeared entirely and seven patients showed a marked improvement. The therapeutic effect of naloxone provides evidence for the role of the endogenous opioid system in the pathogenesis of depersonalization.” The anti convulsion drug Lamotrigine has shown some success in treating symptoms of depersonalisation, often in combination with a Selective serotonin reuptake inhibitor and is the first drug of choice at the depersonalisation research unit at King’s College London.

Research

The Depersonalisation Research Unit at the Institute of Psychiatry in London conducts research into depersonalization disorder. Researchers there use the acronym DPAFU (Depersonalisation and Feelings of Unreality) as a shortened label for the disorder. In a 2020 article in the journal Nature, Vesuna, et al. describe experimental findings which show that layer 5 of the retrosplenial cortex is likely responsible for dissociative states of consciousness in mammals.

What is Derealisation?

Introduction

Derealisation is an alteration in the perception of the external world, causing sufferers to perceive it as unreal, distant, distorted or falsified. Other symptoms include feeling as though one’s environment is lacking in spontaneity, emotional colouring, and depth. It is a dissociative symptom that may appear in moments of severe stress.

Derealisation is a subjective experience pertaining to a person’s perception of the outside world, while depersonalisation is a related symptom characterised by dissociation towards one’s own body and mental processes. The two are commonly experienced in conjunction with one another, but are also known to occur independently.

Chronic derealisation is fairly rare, and may be caused by occipital-temporal dysfunction. Experiencing derealisation for long periods of time or having recurring episodes can be indicative of many psychological disorders, and can cause significant distress among sufferers. However, temporary derealisation symptoms are commonly experienced by the general population a few times throughout their lives, with a lifetime prevalence of up to 26-74% and a prevalence of 31–66% at the time of a traumatic event.

Description

The experience of derealisation can be described as an immaterial substance that separates a person from the outside world, such as a sensory fog, pane of glass, or veil. Individuals may report that what they see lacks vividness and emotional colouring. Emotional response to visual recognition of loved ones may be significantly reduced. Feelings of déjà vu or jamais vu are common. Familiar places may look alien, bizarre, and surreal. One may not even be sure whether what one perceives is in fact reality or not. The world as perceived by the individual may feel as if it were going through a dolly zoom effect. Such perceptual abnormalities may also extend to the senses of hearing, taste, and smell.

The degree of familiarity one has with their surroundings is among one’s sensory and psychological identity, memory foundation and history when experiencing a place. When persons are in a state of derealisation, they block this identifying foundation from recall. This “blocking effect” creates a discrepancy of correlation between one’s perception of one’s surroundings during a derealisation episode, and what that same individual would perceive in the absence of a derealisation episode.

Frequently, derealisation occurs in the context of constant worrying or “intrusive thoughts” that one finds hard to switch off. In such cases it can build unnoticed along with the underlying anxiety attached to these disturbing thoughts, and be recognised only in the aftermath of a realisation of crisis, often a panic attack, subsequently seeming difficult or impossible to ignore. This type of anxiety can be crippling to the affected and may lead to avoidant behaviour. Those who experience this phenomenon may feel concern over the cause of their derealisation. It is often difficult to accept that such a disturbing symptom is simply a result of anxiety, and the individual may often think that the cause must be something more serious. This can, in turn, cause more anxiety and worsen the derealisation. Derealisation also has been shown to interfere with the learning process, with cognitive impairments demonstrated in immediate recall and visuospatial deficits. This can be best understood as the individual feeling as if they see the events in third person; therefore they cannot properly process information, especially through the visual pathway.

People experiencing derealisation describe feeling as if they are viewing the world through a TV screen. This, along with co-morbidities such as depression and anxiety, and other similar feelings attendant to derealisation, can cause a sensation of alienation and isolation between the person suffering from derealisation and others around them. This is particularly the case as Derealisation Disorder is characteristically diagnosed and recognised sparsely in clinical settings. This is in light of general population prevalence being as high as 5%, skyrocketing to as high as 37% for traumatised individuals.

Partial symptoms would also include depersonalisation, a feeling of being an “observer”/having an “observational effect”. As if existing as a separate entity on the planet, with everything happening, being experienced and alternatively perceived through their own eyes (similar to a first person camera in a game, e.g. Television or Computer-Vision).

Causes

Derealisation can accompany the neurological conditions of epilepsy (particularly temporal lobe epilepsy), migraine, and mild TBI (head injury). There is a similarity between visual hypo-emotionality, a reduced emotional response to viewed objects, and derealisation. This suggests a disruption of the process by which perception becomes emotionally coloured. This qualitative change in the experiencing of perception may lead to reports of anything viewed being unreal or detached.

The instances of recurring or chronic derealisation among those who have experienced extreme trauma and/or suffer from post traumatic stress disorder (PTSD) have been studied closely in many scientific studies, whose results indicate a strong link between the disorders, with a disproportionate amount of post traumatic stress patients reporting recurring feelings of derealisation and depersonalisation (up to 30% of all sufferers) in comparison to the general populace (only around 2%), especially in those who experienced the trauma in childhood. Many possibilities have been suggested by various psychologists to help explain these findings, the most widely accepted including that experiencing trauma can cause sufferers to distance themselves from their surroundings and perception, with the aim of subsequently distancing themselves from the trauma and (especially in the case of depersonalisation) their emotional response to it. This could be either as a deliberate coping mechanism or an involuntary, reflexive response depending of circumstance. This possibly not only increases the risk of experiencing problems with derealisation and its corresponding disorder, but with all relevant dissociative disorders. In the case of childhood trauma, not only are children more likely to be susceptible to such a response as they are less able to implement more healthy strategies to deal with the emotional implications of experiencing trauma, there is also a lot of evidence that shows trauma can have a substantial detrimental effect on learning and development, especially since those who experience trauma in childhood are far less likely to have received adequate parenting. These are factors proven to increase susceptibility to maladaptive psychological conditions, which of course includes dissociative disorders and subsequently derealisation symptoms.

Some neurophysiological studies have noted disturbances arising from the frontal-temporal cortex, which could explain the correlation found between derealisation symptoms and temporal lobe disorders. This is further supported by reports of people with frontal lobe epilepsy, with those who suffered epilepsy of the dorsal premotor cortex reporting symptoms of depersonalisation, while those with temporal lobe epilepsy reported experiencing derealisation symptoms. This implies that malfunction of these specific brain regions may be the cause of these dissociative symptoms, or at the very least that these brain regions are heavily involved.

Derealisation can possibly manifest as an indirect result of certain vestibular disorders such as labyrinthitis. This is thought to result from anxiety stemming from being dizzy. An alternative explanation holds that a possible effect of vestibular dysfunction includes responses in the form of the modulation of noradrenergic and serotonergic activity due to a misattribution of vestibular symptoms to the presence of imminent physical danger resulting in the experience of anxiety or panic, which subsequently generate feelings of derealisation. Likewise, derealisation is a common psychosomatic symptom seen in various anxiety disorders, especially hypochondria. However, derealisation is presently regarded as a separate psychological issue due to its presence as a symptom within several pathologies.

Derealization and dissociative symptoms have been linked by some studies to various physiological and psychological differences in individuals and their environments. It was remarked that labile sleep-wake cycles (labile meaning more easily roused) with some distinct changes in sleep, such as dream-like states, hypnogogic, hypnopompic hallucinations, night-terrors and other disorders related to sleep could possibly be causative or improve symptoms to a degree. Derealisation can also be a symptom of severe sleep disorders and mental disorders like depersonalisation disorder, borderline personality disorder, bipolar disorder, schizophrenia, dissociative identity disorder, and other mental conditions.

Cannabis, psychedelics, dissociatives, antidepressants, caffeine, nitrous oxide, albuterol, and nicotine can all produce feelings of derealisation, or sensations mimicking them, particularly when taken in excess. It can also result from alcohol withdrawal or benzodiazepine withdrawal. Opiate withdrawal can also cause feelings of derealisation, often alongside psychotic symptoms such as anxiety, paranoia and hallucinations.

Interoceptive exposure exercises have been used in research settings a means to induce derealisation, as well as the related phenomenon depersonalisation, in people who are sensitive to high levels of anxiety. Exercises with documented successes include timed intervals of hyperventilation or staring at a mirror, dot, or spiral.