Dissociative identity disorder (DID)

Dissociative identity disorder (DID), also known as multiple personality disorder(MPD), is an extremely rare mental disorder characterized by at least two distinct and relatively enduring identities or dissociated personality states that alternately control a person's behavior, and is accompanied by memory impairment for important information not explained by ordinary forgetfulness. These symptoms are not accounted for by substance abuse, seizures, other medical conditions, nor by imaginative play in children. Diagnosis is often difficult as there is considerable comorbidity with other mental disorders. Malingering should be considered if there is possible financial or forensic gain, as well as factitious disorder if help-seeking behavior is prominent.

DID is one of the most controversial psychiatric disorders with no clear consensus regarding its diagnosis or treatment.Research on treatment effectiveness still focuses mainly on clinical approaches and case studies. Dissociative symptoms range from common lapses in attention, becoming distracted by something else, and daydreaming, to pathological dissociative disorders. No systematic, empirically-supported definition of "dissociation" exists.

Although neither epidemiological surveys nor longitudinal studies have been done, it is thought DID rarely resolves spontaneously. Symptoms are said to vary over time.^[6] In general, the prognosis is poor, especially for those with co-morbid disorders. There is little systematic data on the prevalence of DID.^[4] The International Society for the Study of Trauma and Dissociation states that the prevalence is between 1 and 3% in the general population, and between 1 and 5% in inpatient groups in Europe and North America. DID is diagnosed more frequently in North America than in the rest of the world, and is diagnosed three to nine times more often in females than in males.The prevalence of DID increased greatly in the latter half of the 20th century, along with the number of identities (often referred to as "alters") claimed by patients (increasing from an average of two or three to approximately 16). DID is also controversial within the legal system where it has been used as a rarely-successful form of the insanity defense.The 1990s showed a parallel increase in the number of court cases involving the diagnosis.

Dissociative disorders including DID have been attributed to disruptions in memory caused by trauma and other forms of stress, but research on this hypothesis has been characterized by poor methodology. So far, scientific studies, usually focusing on memory, have been few and the results have been inconclusive.An alternative hypothesis for the etiology of DID is as a product of techniques employed by some therapists, especially those using hypnosis, and disagreement between the two positions is characterized by intense debate. DID became a popular diagnosis in the 1970s, 80s and 90s but it is unclear if the actual incidence of the disorder increased, if it was more recognized by clinicians, or if sociocultural factors caused an increase in iatrogenic presentations. The unusual number of diagnoses after 1980, clustered around a small number of clinicians and the suggestibility characteristic of those with DID, support the hypothesis that DID is therapist-induced. The unusual clustering of diagnoses has also been explained as due to a lack of awareness and training among clinicians to recognize cases of DID.

Definitions

Dissociation, the term that underlies the dissociative disorders including DID, lacks a precise, empirical and generally agreed upon definition. A large number of diverse experiences have been termed dissociative, ranging from normal failures in attention to the breakdowns in memory processes characterized by the dissociative disorders. Thus it is unknown if there is a common root underlying all dissociative experiences, or if the range of mild to severe symptoms are a result of different etiologies and biological structures.Other terms used in the literature, including personality, personality state, identity, ego state and amnesia, also have no agreed upon definitions. Multiple competing models exist that incorporate some non-dissociative symptoms while excluding dissociative ones.The most widely used model of dissociation conceptualizes DID as at one extreme of a continuum of dissociation, with flow at the other end, though this model is being challenged.

Some terms have been proposed regarding dissociation. Psychiatrist Paulette Gillig draws a distinction between an "ego state" (behaviors and experiences possessing permeable boundaries with other such states but united by a common sense of self) and the term "alters" (each of which may have a separate autobiographical memory, independent initiative and a sense of ownership over individual behavior) commonly used in discussions of DID.Ellert Nijenhuis and colleagues suggest a distinction between personalities responsible for day-to-day functioning (associated with blunted physiological responses and reduced emotional reactivity, referred to as the "apparently normal part of the personality" or ANP) and those emerging in survival situations (involving fight-or-flight responses, vivid traumatic memories and strong, painful emotions, the "emotional part of the personality" or EP). "Structural dissociation of the personality" is used by van der Hart and colleagues to distinguish dissociation they attribute to traumatic or pathological causes, which in turn is divided into primary, secondary and tertiary dissociation. According to this hypothesis, primary dissociation involves one ANP and one EP, while secondary dissociation involves one ANP and at least two EPs and tertiary dissociation, which is unique to DID, is described as having at least two ANP and at least two EP.^[7] Others have suggested dissociation can be separated into two distinct forms, detachment and compartmentalization, the latter of which, involving a failure to control normally controllable processes or actions, is most evident in DID. Efforts to psychometrically distinguish between normal and pathological dissociation have been made, but they have not been universally accepted.

Signs and symptoms

According to the fifth, Diagnostic and Statistical Manual of Mental Disorders (DSM), DID includes "the presence of two or more distinct identities or personality states" that alternate control of the individual's behavior, accompanied by the inability to recall personal information beyond what is expected through normal forgetfulness.In each individual, the clinical presentation varies and the level of functioning can change from severely impaired to adequate. The symptoms of dissociative amnesia, dissociative fugue and depersonalization disorder are subsumed under the DID diagnosis and are not diagnosed separately. Individuals with DID may experience distress from both the symptoms of DID (intrusive thoughts or emotions) as well as the consequences of the accompanying symptoms (dissociation rendering them unable to remember specific information). The majority of patients with DID report childhood sexual and/or physical abuse, though the accuracy of these reports is controversial.Identities may be unaware of each other and compartmentalize knowledge and memories, resulting in chaotic personal lives.Individuals with DID may be reluctant to discuss symptoms due to associations with abuse, shame and fear. DID patients may also frequently and intensely experience time disturbances.

The number of alters varies widely, with most patients identifying fewer than ten, though as many as 4,500 have been reported. The average number of alters has increased over the past few decades, from two or three to now an average of approximately 16. However it is unclear whether this is due to an actual increase in alters, or simply that the psychiatric community has become more accepting of a high number of alters.The primary identity, which often has the patient's given name, tends to be "passive, dependent, guilty and depressed" with other personalities or "alters" being more active, aggressive or hostile, and often containing more complete memories. Most identities are of ordinary people, though fictional, mythical, celebrity and animal alters have also been reported.

Co-morbid disorders

Most dissociative disorder cases have co-morbid mental disorders, with an average of 8 axis I and 4.5 axis II DSM diagnoses. The psychiatric history frequently contains multiple previous diagnoses of various disorders and treatment failures. The most common presenting complaint of DID is depression, with headaches being a common neurological symptom. Co-morbid disorders can include substance abuse, eating disorders, anxiety, posttraumatic stress disorder (PTSD) and personality disorders.A majority of those diagnosed with DID meet the criteria for DSM axis II personality disorders such as borderline personality disorder; a significant minority meet the criteria for avoidant personality disorder and other personality disorders. Further, data supports a high level of psychotic symptoms in DID, and that both schizophrenia and DID have histories of trauma. Individuals diagnosed with DID also demonstrate the highest hypnotizability of any clinical population. The large number of symptoms presented by individuals diagnosed with DID has led to some clinicians to suggest that, rather than being a separate disorder, diagnosis of DID is actually an indication of the severity of the other disorders diagnosed in the patient.

Borderline personality disorder

In 1993 a group of researchers reviewed both DID and borderline personality disorder (BPD), concluding that DID was an epiphenomenon of BPD, with no tests or clinical description capable of distinguishing between the two. Their conclusions about the empirical proof of DID were echoed by a second group, who still believed the diagnosis existed, but while the knowledge to date did not justify DID as a separate diagnosis, it also did not disprove its existence. Reviews of medical records and psychological tests indicated that the majority of DID patients could be diagnosed with BPD instead, though about a third could not be, suggesting DID does exist but may be over-diagnosed. Between 50–66% of patients also meet the criteria for BPD, and nearly 75% of patients with BPD also meet the criteria for DID with considerable overlap between the two conditions in terms of personality traits, cognitive and day-to-day functioning, and ratings by clinicians. Both groups also report higher than general population rates of physical and sexual abuse, and patients with BPD also score highly on measures of dissociation. Even using strict diagnostic criteria, it can be difficult to distinguish between dissociative disorders and BPD (as well as bipolar disorder and schizophrenia). The DSM-IV-TR states that acts of self-mutilation, impulsivity and rapid changes in interpersonal relationships "may warrant a concurrent diagnosis of Borderline Personality Disorder". Steven Lynn and colleagues have suggested that the significant overlap between BPD and DID may be a contributing factor to the development of iatrogenic DID, in that hidden alters suggested by therapists who propose a diagnosis of DID provides an explanation to patients for the behavioral instability, self-mutilation, unpredictable mood changes and actions they experience.

Causes

The cause of DID is controversial, with debate occurring between supporters of different hypotheses: that DID is a reaction to trauma; that DID is produced iatrogenically by inappropriate psychotherapeutic techniques that cause a patient to enact the role of a patient with DID; and newer hypotheses involving memory processing that allows for the possibility that trauma-causing dissociation can occur after childhood in DID, as it does in PTSD. It has been suggested that all the trauma-based and stress-related disorders be placed in one category that would include both DID and PTSD. Disturbed and altered sleep has also been suggested as having a role in dissociative disorders in general and specifically in DID.

Research is needed to determine the prevalence of the disorder in those who have never been in therapy, and the prevalence rates across cultures. These central issues relating to the epidemiology of DID remain largely unaddressed despite several decades of research. The debates over the causes of DID also extend to disagreements over how the disorder is assessed and treated.

Developmental trauma

People diagnosed with DID often report that they have experienced severe physical and sexual abuse, especially during early to mid-childhood, (although the accuracy of these reports has been disputed) and others report an early loss, serious medical illness or other traumatic event. They also report more historical psychological trauma than those diagnosed with any other mental illness. Severe sexual, physical, or psychological trauma in childhood has been proposed as an explanation for its development; awareness, memories and emotions of harmful actions or events caused by the trauma are removed from consciousness, and alternate personalities or subpersonalities form with differing memories, emotions and behavior. DID is attributed to extremes of stress or disorders of attachment. What may be expressed as post-traumatic stress disorder in adults may become DID when occurring in children, possibly due to their greater use of imagination as a form of coping.Possibly due to developmental changes and a more coherent sense of self past the age of six, the experience of extreme trauma may result in different, though also complex, dissociative symptoms and identity disturbances. A specific relationship between childhood abuse, disorganized attachment, and lack of social support are thought to be a necessary component of DID. Other suggested explanations include insufficient childhood nurturing combined with the innate ability of children in general to dissociate memories or experiences from consciousness.

Delinking early trauma from the etiology of dissociation has been explicitly rejected by those supporting the early trauma model. However, 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.Giesbrecht et al. have suggested there is no actual empirical evidence linking early trauma to dissociation, and instead suggest that problems with neuropsychological functioning, such as increased distractibility in response to certain emotions and contexts, account for dissociative features.A middle position hypothesizes that trauma, in some situations, alters neuronal mechanisms related to memory. Evidence is increasing that dissociative disorders are related both to a trauma history and to "specific neural mechanisms". It has also been suggested that there may be a genuine but more modest link between trauma and DID, with early trauma causing increased fantasy-proneness, which may in turn render individuals more vulnerable to socio-cognitive influences surrounding the development of DID.

Therapist induced

The prevailing post-traumatic model of dissociation and dissociative disorders is contested. It has been hypothesized that symptoms of DID may be created by therapists using techniques to "recover" memories (such as the use of hypnosis to "access" alter identities, facilitate age regression or retrieve memories) on suggestible individuals.Referred to as the "sociocognitive model" (SCM), it proposes that DID is due to a person consciously or unconsciously behaving in certain ways promoted by cultural stereotypes, with unwitting therapists providing cues through improper therapeutic techniques. This behavior is enhanced by media portrayals of DID.

Proponents of the SCM note that the bizarre dissociative symptoms are rarely present before intensive therapy by specialists in the treatment of DID who, through the process of eliciting, conversing with and identifying alters, shape, or possibly create the diagnosis. While proponents note that DID is accompanied by genuine suffering and the distressing symptoms, and can be diagnosed reliably using the DSM criteria, they are skeptical of the traumatic etiology suggested by proponents. The characteristics of people diagnosed with DID (hypnotizability, suggestibility, frequent fantasization and mental absorption) contributed to these concerns and those regarding the validity of recovered memories of trauma.Skeptics note that a small subset of doctors are responsible for diagnosing the majority of individuals with DID. Psychologist Nicholas Spanos and others have suggested that in addition to iatrogenesis, DID may be the result of role-playing rather than alternative identities, though others disagree, pointing to a lack of incentive to manufacture or maintain separate identities and point to the claimed histories of abuse. Other arguments for the iatrogenic position, include the lack of children diagnosed with DID, the sudden spike in incidence after 1980 (although DID was not a diagnosis until DSM-IV, published in 1994), the absence of evidence of increased rates of child abuse, the appearance of the disorder almost exclusively in individuals undergoing psychotherapy, particularly involving hypnosis, the presences of bizarre alternate identities (such as those claiming to be animals or mythological creatures) and an increase in the number of alternate identities over time(as well as an initial increase in their number as psychotherapy begins in DID-oriented therapy.) These various cultural and therapeutic causes occur within a context of pre-existing psychopathology, notably borderline personality disorder, which is commonly co-morbid with DID. In addition, presentations can vary across cultures, such as Indian patients who only switch alters after a period of sleep — which is commonly how DID is presented by the media within that country.

The iatrogenic position is strongly linked to the false memory syndrome, coined by the False Memory Syndrome Foundation in reaction to memories recovered by a range of controversial therapies whose effectiveness is unproven. Such a memory could be used to make afalse allegation of child sexual abuse. There is little consensus between the iatrogenic and traumagenic positions regarding DID.Proponents of the iatrogenic position suggest a small number of clinicians diagnosing a disproportionate number of cases would provide evidence for their position though it has also been claimed that higher rates of diagnosis in specific countries like the United States, may be due to greater awareness of DID. Lower rates in other countries may be due to an artificially low recognition of the diagnosis.