The majority of patients with DID report childhood sexual or physical abuse, though the accuracy of these reports is controversial. Amnesia between identities may be asymmetrical; identities may or may not be aware of what is known by another. 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.Around half of people with DID have fewer than 10 identities and most have fewer than 100; although as many as 4,500 have been reported. (p 503) The average number of identities 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 identities, or simply that the psychiatric community has become more accepting of a high number of compartmentalized memory components. Comorbid disorders
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. Comorbid disorders can include substance use disorder, eating disorders, anxiety disorders, bipolar disorder, and personality disorders. A significant percentage of those diagnosed with DID have histories of borderline personality disorder and post-traumatic stress disorder (PTSD). Presentations of dissociation in people with schizophrenia differ from those with DID as not being rooted in trauma, and this distinction can be effectively tested, although both conditions share a high rate of dissociative auditory hallucinations.
Etzel Cardena and David Gleaves believed the over-representation of DID in North America was the result of increased awareness and training about the condition which had formerly been missing. History
Early references
In the 19th century, "dédoublement", or "double consciousness", the historical precursor to DID, was frequently described as a state of sleepwalking, with scholars hypothesizing that the patients were switching between a normal consciousness and a "somnambulistic state".An intense interest in spiritualism, parapsychology and hypnosis continued throughout the 19th and early 20th centuries, running in parallel with John Lockes views that there was an association of ideas requiring the coexistence of feelings with awareness of the feelings. Hypnosis, which was pioneered in the late 18th century by Franz Mesmer and Armand-Marie Jacques de Chastenet, Marques de Puységur, challenged Lockes association of ideas. Hypnotists reported what they thought were second personalities emerging during hypnosis and wondered how two minds could coexist. In the 19th century, there were a number of reported cases of multiple personalities which Rieber estimated would be close to 100. Epilepsy was seen as a factor in some cases, and discussion of this connection continues into the present era.By the late 19th century, there was a general acceptance that emotionally traumatic experiences could cause long-term disorders which might display a variety of symptoms. These conversion disorders were found to occur in even the most resilient individuals, but with profound effect in someone with emotional instability like Louis Vivet (1863–? ), who had a traumatic experience as a 17-year-old when he encountered a viper.