Experimental tests of memory suggest that patients with DID may have improved memory for certain tasks, which has been used to criticize the hypothesis that DID is a means of forgetting or suppressing memory. Patients also show experimental evidence of being more fantasy-prone, which in turn is related to a tendency to over-report false memories of painful events. Diagnosis
General
The fifth, revised edition of the American Psychiatric Associations Diagnostic and Statistical Manual of Mental Disorders (DSM-5) diagnoses DID according to the diagnostic criteria found under code 300.14 (dissociative disorders). DID is often initially misdiagnosed because clinicians receive little training about dissociative disorders or DID, and often use standard diagnostic interviews that do not include questions about trauma, dissociation or post-traumatic symptoms. (p 118) This contributes to difficulties diagnosing the disorder and clinician bias.DID is rarely diagnosed in children, despite the average age of appearance of the first alter being three years old. The criteria require that an individual be recurrently controlled by two or more discrete identities or personality states, accompanied by memory lapses for important information that is not caused by alcohol, drugs or medications and other medical conditions such as complex partial seizures. In children the symptoms must not be better explained by "imaginary playmates or other fantasy play". Diagnosis is normally performed by a clinically trained mental health professional such as a psychiatrist or psychologist through clinical evaluation, interviews with family and friends, and consideration of other ancillary material.
Arguments have been made for allowing diagnosis through the presence of some, but not all of the characteristics of DID rather than the current exclusive focus on the two least common and noticeable features. The DSM-IV-TR criteria have also been criticized for being tautological, using imprecise and undefined language and for the use of instruments that give a false sense of validity and empirical certainty to the diagnosis. The DSM-5 updated the definition of DID in 2013, summarizing the changes as:
Several changes to the criteria for dissociative identity disorder have been made in DSM-5. First, Criterion A has been expanded to include certain possession-form phenomena and functional neurological symptoms to account for more diverse presentations of the disorder. Second, Criterion A now specifically states that transitions in identity may be observable by others or self-reported. Third, according to Criterion B, individuals with dissociative identity disorder may have recurrent gaps in recall for everyday events, not just for traumatic experiences. Other text modifications clarify the nature and course of identity disruptions. Between 1968 and 1980, the term that was used for dissociative identity disorder was "Hysterical neurosis, dissociative type". The APA wrote in the second edition of the DSM: "In the dissociative type, alterations may occur in the patients state of consciousness or in his identity, to produce such symptoms as amnesia, somnambulism, fugue, and multiple personality." The number of cases sharply increased in the late 1970s and throughout the 80s, and the first scholarly monographs on the topic appeared in 1986.