Diagnostic Features
The essential feature of Dissociative Identity Disorder is the presence of two or more distinct identities or personality states (Criterion A) that recurrently take control of behavior (Criterion B). There is an inability to recall important personal information, the extent of which is too great to be explained by ordinary forgetfulness (Criterion C). The disturbance is not due to the direct physiological effects of a substance or a general medical condition (Criterion D). In children, the symptoms cannot be attributed to imaginary playmates or other fantasy play.
Dissociative Identity Disorder reflects a failure to integrate various aspects of identity, memory, and consciousness. Each personality state may be experienced as if it has a distinct personal history, self-image, and identity, including a separate name. Usually there is a primary identity that carries the individual’s given name and is passive, dependent, guilty, and depressed. The alternate identities frequently have different names and characteristics that contrast with the primary identity (e.g., are hostile, controlling, and self-destructive). Particular identities may emerge in specific circumstances and may differ in reported age and gender, vocabulary, general knowledge, or predominant affect. Alternate identities are experienced as taking control in sequence, one at the expense of the other, and may deny knowledge of one another, be critical of one another, or appear to be in open conflict. Occasionally, one or more powerful identities allocate time to the others. Aggressive or hostile identities may at times interrupt activities or place the others in uncomfortable situations.
Individuals with this disorder experience frequent gaps in memory for personal history, both remote and recent. The amnesia is frequently asymmetrical. The more passive identities tend to have more constricted memories, whereas the more hostile, controlling, or “protector” identities have more complete memories. An identity that is not in control may nonetheless gain access to consciousness by producing auditory or visual hallucinations (e.g., a voice giving instructions). Evidence of amnesia may be uncovered by reports from others who have witnessed behavior that is disavowed by the individual or by the individual’s own discoveries (e.g., finding items of clothing at home that the individual cannot remember having bought). There may be loss of memory not only for recurrent periods of time, but also an overall loss of biographical memory for some extended period of childhood, adolescence, or even adulthood. Transitions among identities are often triggered by psychosocial stress. The time required to switch from one identity to another is usually a matter of seconds, but, less frequently, may be gradual. Behavior that may be frequently associated with identity switches include rapid blinking, facial changes, changes in voice or demeanor, or disruption in the individual’s train of thoughts. The number of identities reported ranges from 2 to more than 100. Half of reported cases include individuals with 10 or fewer identities.
Associated Features and Disorders
Associated descriptive features and mental disorders. Individuals with Dissociative Identity Disorder frequently report having experienced severe physical and sexual abuse, especially during childhood. Controversy surrounds the accuracy of such reports, because childhood memories may be subject to distortion and some individuals with this disorder are highly hypnotizable and especially vulnerable to suggestive influences. However, reports by individuals with Dissociative Identity Disorder of a past history of sexual or physical abuse are often confirmed by objective evidence. Furthermore, persons responsible for acts of physical and sexual abuse may be prone to deny or distort their behavior. Individuals with Dissociative Identity Disorder may manifest posttraumatic symptoms (e.g., nightmares, flashbacks, and startle responses) or Posttraumatic Stress Disorder. Self-mutilation and suicidal and aggressive behavior may occur. Some individuals may have a repetitive pattern of relationships involving physical and sexual abuse. Certain identities may experience conversion symptoms (e.g., pseudoseizures) or have unusual abilities to control pain or other physical symptoms. Individuals with this disorder may also have symptoms that meet criteria for Mood, Substance-Related, Sexual, Eating, or Sleep Disorders. Self-mutilative behavior, impulsivity, and sudden and intense changes in relationships may warrant a concurrent diagnosis of Borderline Personality Disorder.
Associated laboratory findings. Individuals with Dissociative Identity Disorder score toward the upper end of the distribution on measures of hypnotizability and dissociative capacity. There are reports of variation in physiological function across identity states (e.g., differences in visual acuity, pain tolerance, symptoms of asthma, sensitivity to allergens, and response of blood glucose to insulin).
Associated physical examination findings and general medical conditions. There may be scars from self-inflicted injuries or physical abuse. Individuals with this disorder may have migraine and other types of headaches, irritable bowel syndrome, and asthma.
Specific Culture, Age, and Gender Features
Dissociative Identity Disorder has been found in individuals from a variety of cultures around the world. In preadolescent children, particular care is needed in making the diagnosis because the manifestations may be less distinctive than in adolescents and adults. Dissociative Identity Disorder is diagnosed three to nine times more frequently in adult females than in adult males; in childhood, the female-to-male ratio may be more even, but data are limited. Females tend to have more identities than do males, averaging 15 or more, whereas males average approximately 8 identities.
Prevalence
The sharp rise in reported cases of Dissociative Identity Disorder in the United States in recent years has been subject to very different interpretations. Some believe that the greater awareness of the diagnosis among mental health professionals has resulted in the identification of cases that were previously undiagnosed. In contrast, others believe that the syndrome has been overdiagnosed in individuals who are highly suggestible.
Course
Dissociative Identity Disorder appears to have a fluctuating clinical course that tends to be chronic and recurrent. The average time period from first symptom presentation to diagnosis is 6-7 years. Episodic and continuous courses have both been described. The disorder may become less manifest as individuals age beyond their late 40s, but may reemerge during episodes of stress or trauma or with Substance Abuse.
Familial Pattern
Several studies suggest that Dissociative Identity Disorder is more common among the first-degree biological relatives of persons with the disorder than in the general population.
Differential Diagnosis
Dissociative Identity Disorder must be distinguished from symptoms that are caused by the direct physiological effects of a general medical condition (e.g., seizure disorder). This determination is based on history, laboratory findings, or physical examination. Dissociative Identity Disorder should be distinguished from dissociative symptoms due to complex partial seizures, although the two disorders may co-occur. Seizure episodes are generally brief (30 seconds to 5 minutes) and do not involve the complex and enduring structures of identity and behavior typically found in Dissociative Identity Disorder. Also, a history of physical and sexual abuse is less common in individuals with complex partial seizures. EEG studies, especially sleep deprived and with nasopharyngeal leads, may help clarify the differential diagnosis.
Symptoms caused by the direct physiological effects of a substance can be distinguished from Dissociative Identity Disorder by the fact that a substance (e.g., a drug of abuse or a medication) is judged to be etiologically related to the disturbance.
The diagnosis of Dissociative Identity Disorder takes precedence over Dissociative Amnesia, Dissociative Fugue, and Depersonalization Disorder. Individuals with Dissociative Identity Disorder can be distinguished from those with trance and possession trance symptoms that would be diagnosed as Dissociative Disorder Not Otherwise Specified by the fact that those with pathological trance and possession trance symptoms typically describe external spirits or entities that have entered their bodies and taken control.
The differential diagnosis between Dissociative Identity Disorder and a variety of other mental disorders (including Schizophrenia and other Psychotic Disorders, Bipolar Disorder, With Rapid Cycling, Anxiety Disorders, Somatization Disorders, and Personality Disorders) is complicated by the apparently overlapping symptom presentations. For example, the presence of more than one dissociated personality state may be mistaken for a delusion or the communication from one identity to another may be mistaken for an auditory hallucination, leading to confusion with the Psychotic Disorders, and shifts between identity states may be confused with cyclical mood fluctuations leading to confusion with Bipolar Disorder). Factors that may support a diagnosis of Dissociative Identity Disorder are the presence of clear-cut dissociative symptomatology with sudden shifts in identity states, the persistence and consistency of identity-specific demeanors and behaviors over time, reversible amnesia, evidence of dissociative behavior that predates the clinical or forensic presentation (e.g., reports by family or co-workers), and high scores on measures of dissociation and hypnotizability in individuals who do not have the characteristic presentations of another mental disorder.
Dissociative Identity Disorder must be distinguished from Malingering in situations in which there may be financial or forensic gain and from Factitious Disorder in which there may be a pattern of help-seeking behavior.
Diagnostic criteria for 300.14 Dissociative Identity Disorder
A. The presence of two or more distinct identities or personality states (each with its own relatively enduring pattern of perceiving, relating to, and thinking about the environment and self).
B. At least two of these identities or personality states recurrently take control of the person’s behavior.
C. Inability to recall important personal information that is too extensive to be explained by ordinary forgetfulness.
D. The disturbance is not due to the direct physiological effects of a substance (e.g., blackouts or chaotic behavior during Alcohol Intoxication) or a general medical condition (e.g., complex partial seizures). Note: In children, the symptoms are not attributable to imaginary playmates or other fantasy play.
