A rare condition in which separate personalities exist in the same person is called

Etiology and risk factors

Dissociative identity disorder is usually caused by excessive stress or trauma during childhood. In normal development, the sense of a unified identity develops from a variety of experiences and sources. In a child who is overwhelmed, many factors that should have blended together or become integrated over time instead remain separate. Chronic, severe emotional, physical, or sexual abuse and neglect often lead to the development of dissociative identity disorder. In fact, about 90% of patients with the disorder have experienced some type of early trauma. Other contributing factors include important early losses, including death of a parent, as well as serious medical illnesses or other overwhelming stressors. Children who are severely mistreated may develop in distinct phases (as opposed to the more healthy seamless development) that include different emotions, memories, and perceptions, which develop separately and therefore are especially vulnerable to not being naturally integrated into a singular developing “self” or personality. Over years, they may develop a way to “escape” mistreatment by detaching themselves or “disappearing” into their own minds. Each phase of development or traumatic event may cause a different identity to be created. Standardized testing of patients with dissociative identity disorder reveals high scores for being susceptible to hypnosis, and for dissociation.

Dissociative Identity Disorder (Multiple Personality Disorder)

DID is defined by the presence of two or more distinct identities or personality states that recurrently take control of behavior. This disorder represents the failure to integrate various aspects of identity, memory, and consciousness. Characteristics of this disorder are memory disturbances and amnesia. In contrast to other dissociative disorders, the degree of amnesia experienced in DID is usually asymmetrical. That is, it selectively involves different areas of autobiographical information, i.e., alters (personality states or identities) differ in the degree of amnesia for the experiences of other alters and the access to autobiographical information.

Usually there is a primary or host personality that carries the patient's given name. Often the host is not completely aware of the presence of alters. Because of the presence of amnestic barriers, different personalities may have varying levels of awareness of the existence of other personalities. On average there are 2 to 4 personalities present at the time of diagnosis, and usually up to 13 to 15 personalities are discovered during the course of treatment.

The symptoms that usually prompt patients or their families to seek treatment include memory deficits, moodiness, erratic and unpredictable behavior, depression, self-mutilation, suicidal ideation or attempts, and the overt manifestation of an alternate personality. Transition from one personality to another is usually sudden and is commonly triggered by environmental/interpersonal factors.

Alter identities may have different names, sexes, ages, and personal characteristics and often reflect various attempts to cope with difficult issues and problems. Alters can have a name and well-formed personalities, e.g., Rose, an 8-year-old girl, or can be named after their function or description, e.g., the Angry One.

The factors that can lead to the development of DID are quite varied, but most authors seem to agree that physical and sexual abuse during childhood is the most commonly found etiological factor in these patients. In fact, a history of sexual and/or physical abuse has been reported in 70–97% of patients suffering from DID, with incest being the most common form of sexual trauma (68%). Other forms of childhood trauma that are associated with later development of DID include physical abuse other than sexual abuse (75%), neglect, confinement, severe intimidation with physical harm, witnessing physical or sexual abuse of a sibling, witnessing the violent death of a relative or close friend, traumatic physical illness on self, and near-death experiences.

The actual incidence and prevalence of this disorder are unclear. The estimated prevalence of DID in the general population has been reported to range from 0.01 to 1%. The average time from the appearance of symptoms to an accurate diagnosis is 6 years. The average age at diagnosis is 29 to 35 years. It has been described to be more common in women than in men by a ratio of 3–9:1. Female patients are also reported to present more personalities (average of 15) than men (average of 8).

There is a high incidence of comorbid psychiatric and medical syndromes. Of the psychiatric disorders, depression is the most common (85–88%), followed by posttraumatic stress disorder, BPDs, and substance abuse. There are a number of other psychiatric symptoms common to patients with DID, including insomnia, suicide attempts or gestures, self-destructive behaviors, phobias, anxiety, panic attacks, auditory and visual hallucinations, somatization, conversion reactions, and psychotic-like behavior.

As in cases of dissociative amnesia and fugue, the differential diagnosis of dissociative disorders includes an organic condition (e.g., temporal lobe epilepsy, brain malignancy, head trauma, medication side effect, drug abuse, and intoxication), other dissociative disorders, psychotic disorders (e.g., schizophrenia), factitious disorder, and malingering.

Multiple personality disorder and other dissociative disorders

Multiple personality disorder (MPD) is a psychiatric disorder characterized by the spontaneous generation of an alternate version of self. The personalities have distinctive styles of expressing themselves and they often posses separate names, genders, ages, family histories, and lifestyles. They may have different occupations, sets of friends, and social networks. Sometimes, the physiologic differences between the various MPD personalities can be really surprising: differences in IQ, handiness, handwriting style, visual acuity, and other features have been reported in the literature. Although personalities can be complementary to one other, very often one can distinguish an original personality from another personality that acts like a persecutor.

MPD is likely to occur as an attempt to integrate the consequences of traumatic experiences in individuals with high suggestibility. The exposure to a severe and emotionally overwhelming physical or mental trauma could somehow provoke dissociative disorders, as if the individual is unable to cope with the trauma of maintaining unit his own personality.

MPD is a controversial subject. Some scholars insist that it usually goes undetected; others have criticized the conception of childhood trauma. Actually, an explicit trauma may or may not be present. Trauma may also occur only in the internal, emotional world of the subject, without any detectable recognizable events is. This debate directly concerns the foundation of psychoanalysis.

MPD poses several puzzling problems for the theory of personal identity; this also holds true also for other dissociative disorders. Some patients are able to dissociate memories of single events (dissociative amnesia), or memories of complex behaviors, which they can accomplish in a trancelike state (dissociative fugue, somnambulism, trance disorders). In the final analysis, dissociation appears to be an effort to repair models of self and others, namely, dissociative disorders show that we are constantly creating versions of ourselves and others, and these versions depend upon the social contexts and some inner capacities to select our memories both consciously and unconsciously.

Moral philosophers may be intrigued by this continuum, which begins with conscious fiction, passes through self-deception, akrasia, and autosuggestion, and arrives at dissociative disorders. Actually, there is a psychiatric syndrome that clearly enlightens all these aspects, called Ganser’s syndrome (currently classified in DSM-IV among Dissociative Disorders not otherwise specified). Ganserian patients are usually jailers who pretend to be mad. Their fictitious symptoms include bizarre delusions, amnesia, and confabulation. After a certain time Ganserian patients begin to believe more and more in their fiction until they develop a true ‘false psychosis,’ namely, dissociative disorders out of the control of their will that faithfully reproduce the original mental disturbance. From a legal and ethical perspective it is highly controversial whether Ganserian patients should be treated as if they are remarkable simulators or actual mentally disturbed people.

Types of Dissociative Disorders Associated with Sleep

There are five diagnostic categories of DDs in DSM-IV47 including (1) dissociative identity disorder (formerly multiple personality disorder), (2) dissociative fugue, (3) dissociative amnesia, (4) depersonalization disorder, and (5) dissociative disorder not otherwise specified (DD NOS). Of these, three are considered SRDD: dissociative identity disorder, dissociative fugue, and DD NOS. Most but not all patients with SRDD have both daytime DD episodes as well as previous episodes of SRDD.1,48

Dissociative Identity Disorder (DID)

The phenomena subsumed under DID have been previously called double or multiple personality, but the DSM-IV changed the name to underline that the core of the condition is not the presence of many personalities, but the failure to integrate various aspects of the individual into a single personality. This terminological change has the implication that a unified personality is an achievement rather than a given. Thus, the current therapeutic goal in the treatment of DID is to integrate different aspects or states of the person so that the person can partake of a common memory, self-attribution, and control, rather than trying to find the real personality, as was the goal earlier on.

DID is defined by the DSM-5 as experienced or observed disruption of identity characterized by two or more distinct personality states or experiences of possession, involving marked discontinuity in the senses of self and agency, and with alterations in affect, memory, states of consciousness, and other psychological processes. Another diagnostic requirement is psychogenic amnesia, and the symptoms must create marked distress and/or impairment and not just be part of an accepted cultural practice. DID is the most severe of the DD and typically subsumes a number of other symptoms, including depersonalization, hearing voices not attributed to the self, episodes of unawareness/unresponsiveness, experiences of self-alteration, anxiety, depression, affective lability (including self-injury and suicide attempts), chronic anxiety, phobias, conversion and other somatization problems, substance abuse, and eating, sexual, and personality symptoms (particularly avoidant and borderline syndromes within the last category). This multiplicity of symptoms has led some authors to propose that the lack of identity integration is not as important as the multiplicity of symptoms, which helps explain why many patients with DID have a history of many previous diagnoses, often of a mood disorder or schizophrenia, before receiving the DID one. It has also been observed that the severity and patterning of symptoms can vary across individuals and times. There are DID patients who can function quite well and may even go undetected by those around them, whereas other patients may at times become frankly psychotic.

Some authors have questioned the validity of this diagnosis but have failed to provide empirical support for an iatrogenic hypothesis. On the other hand, literature reviews and empirical studies support the validity and reliability of the DID diagnosis, and memory and neuroimaging studies have been consistent with the DID patients' reports that they experience alternate, not consciously integrated, psychophysiological states, and are not just “faking” them.

Regarding etiological factors, in a number of studies, the vast majority of DID patients have reported severe and chronic forms of early abuse. Some critics have countered that such reports, coming from highly hypnotizable individuals are suspect, but other studies have shown that the search for some type of independent corroboration, which may be very difficult after many years have elapsed, has been substantially consistent with the patients' reports. Nonetheless, it is clear that the vast majority of children who suffer severe abuse or neglect do not develop DID, thus other factors have to be involved. A genetic predisposition to dissociate interacting with some form of disorganized or disrupted attachment seem to also be important etiological factors. Traumatic events, particularly in the context of problems in attachment, are important particularly if they occur early in life, when a sense of an integrated self is being developed and is thus vulnerable to disruptions. The differential diagnoses include schizophrenia, affective disorders, and seizure disorder.

The DSM-5 has now included pathological spirit possession under DID. Spirit possession is typically characterized by a temporary alteration of consciousness defined by the replacement of the usual sense of identity by another one (which may be recognized as an ancestor or a spiritual force), stereotyped behaviors attributed to the possessing entity, and typically full or partial amnesia for the possession episode. Most spirit possessions are not pathological and are associated with religious or other rituals. Research has shown that many if not most devotees who experience possession in a ritual setting evidence good psychological adjustment. Nonetheless, in some cases in both industrialized and nonindustrialized societies, possessions may occur outside of cultural norms, be dysfunctional, and/or produce distress, thus becoming pathological.

Perhaps the psychoses are the closest disorders to DID, but a general distinction is that individuals with DID may exhibit organized (but limited) identities, rather than present the blatant cognitive disorganization and failure of reality testing in schizophrenia.

Dissociative identity changes

In some forms of dissociative identity disorder and the similar phenomenon of “lucid possession” (Oesterreich, 1974), the subject is aware of the mental contents of an alternate personality or possessing agent but otherwise unable to control his or her speech or actions (Deeley et al., 2014). An experimental model of these experiences and attributions of control by another agent involved a suggestion of an engineer conducting research into limb movement. The engineer had found a way to enter the subject and control movement from within. The subject was aware of the thoughts and motives of this possessing agent but unable to control the hand movements produced by it. Suggested control by the external agent was associated with an increase in functional connectivity between M1 (a key movement implementation region) and BA 10, demonstrating functional coupling with brain regions involved in the representation of agency in experiences of loss of motor control to another agent (Deeley et al., 2014).

Dissociative Identity Disorder

Perhaps the most severe reaction to trauma is evident when symptoms of dissociative identity disorder (DID) are present. In this disorder, the trauma that the child experienced was so severe that the personality became fragmented and various components that normally become integrated throughout development begin to coexist independently. Separate identities often take on different names, although this may not be apparent when symptoms begin during early childhood. When these ‘alters’ take over the ‘host’ personality, the patient exhibits distinct changes in attitude, behavior, and demeanor, and these differences are much more pronounced than those evident during normal mood changes. Severe anxiety is often present and may be connected with specific settings, people, or situations. In rare and severe cases, psychosis may co-occur, especially during times of intense anxiety and dissociation.

DID is rare in adults and extremely rare in children. Although the vast majority of cases seen in adulthood are thought to begin in childhood, as a result of severe child abuse, the symptoms associated with this syndrome are rarely evident in childhood, and prodromal disturbance may be evident, characterized by anxiety, moodiness, fear and avoidance of certain people or settings, and other disturbances (for example, sleep problems). The pattern characteristic of DID (distinct switching of alters that take over the host’s body) is not usually recognizable until late adolescence or adulthood.

As with ASD or PTSD, when clinicians encounter children or adolescents who present symptoms that may be characteristic of DID, all symptom groups must be managed. Intensive psychological and pharmacological treatment is likely to be necessary, and psychosis should not be treated in isolation. While using an antipsychotic may be helpful, it is not likely to be effective unless the other symptoms are also being addressed. Unfortunately, this will usually mean that multiple supplements, in addition to intense psychotherapy, will need to be used, and such cases should be approached with extreme caution.

Dissociative Disorders

96.

What historical elements may be common in dissociative disorders such as dissociative identity disorder, dissociative amnesia, and depersonalization/derealization disorder?

A history of severe childhood physical, sexual, and emotional abuse, or a history of traumatic wartime or natural disaster experiences is common in these disorders. Dissociation or depersonalization can be part of the normal experience during extreme situations, but for people with dissociative disorders the symptoms are severe, persistent, and disabling.

Dissociative amnesias and the amnesia of dementia (e.g., Alzheimer’s disease) can be distinguished by what features?

While personality can change in some dementias, dissociative amnesias involve loss or alteration of identity. Furthermore, dissociative amnesia is retrograde (as opposed to the typically anterograde—deficit of new learning—amnesia of dementia), isolated to personal information, and associated with a traumatic event.

Emotionally unstable/borderline personality disorder, multiple personality disorder and psychotic symptoms

The diagnosis of borderline personality disorder and its differentiation from other personality disorders is highly variable in clinical practice. The diagnosis of multiple personality disorder is even more controversial and it is one that is rarely made outside North America. It has been renamed dissociative identity disorder in DSM-IV. A number of studies have detected high rates of childhood sexual abuse in patients with borderline personality disorder. Figures range from 40% up to 80%. Rates of personality disorder diagnosis are raised in both men and women according to recent findings (Spataro et al 2004). Although the higher incidence of borderline personality disorder in women has been linked to increased incidence of childhood sexual abuse in girls (Herman et al 1989), certain features of borderline personality disorder, such as suicidal or self-harming behaviour, affective instability and depression, have all been established independently as typical sequelae in adult survivors of sexual abuse. It seems likely that a borderline personality organization results from aspects of severe childhood sexual abuse. Figueroa and Silk (1997) have found that patients diagnosed with borderline personality disorder are less likely to give a history of mild or transient abuse and more likely to give a history of severe and/or long-lasting abuse than patients in other diagnostic groups.

A number of studies have linked multiple personality disorder with a history of childhood sexual abuse, generally finding rates of 70–90% (Ross et al 1990). Many of the studies are flawed by the small number of patients involved and the lack of standardized criteria for the diagnosis.

Few studies have looked at the association of childhood sexual abuse with psychotic illnesses, and studies that do exist have tended not to differentiate between physical and sexual abuse. Dissociative symptoms may overlap with psychotic symptoms and contribute to an atypical presentation (Goff et al 1991). A study of first-episode psychosis found a prevalence rate of childhood abuse (both physical and sexual or combined) of 53% (Greenfield et al 1994). In the large prospective study by Spataro et al (2004) there is a strong link with many mental disorders but not for schizophrenia.

Definition and Characteristic Findings