A new King's College London study supports the notion that multiple personality disorder is rooted in traumatic experiences such as neglect or abuse in childhood, rather than being related to suggestibility or proneness to fantasy.
Multiple personality disorder, more recently known as dissociative identity disorder (DID), is thought to affect approximately one percent of the general population, similar to levels reported for schizophrenia.
People who are eventually diagnosed with DID have often had several earlier misdiagnoses, including schizophrenia or bipolar disorder. DID is characterised by the presence of two or more distinct 'identities' or 'personality states' - each with their own perception of the environment and themselves.
Despite being recognised in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) controversy remains around the diagnosis. Some experts argue that DID is linked to trauma such as chronic emotional neglect and/or emotional, physical, or sexual abuse from early childhood. Others hold a non-trauma related view of DID, whereby the condition is believed to be related to fantasy proneness, suggestibility, simulation or enactment.
This new study, published today in Acta Psychiatrica Scandinavica, provides support for the trauma model of DID and challenges the core hypothesis of the fantasy model, according to the study authors.
The researchers compared 65 women on a variety of questionnaires which measured traumatic experiences, suggestibility, fantasy proneness and malingering of psychiatric symptoms. The sample comprised women with a genuine diagnosis of DID, female actors who were asked to simulate DID, women with post traumatic stress disorder (PTSD) and healthy controls.
They found that patients with DID were not more fantasy prone or suggestible and did not generate more false memories compared to patients with PTSD, DID simulating controls and controls.
The researchers found a continuum of trauma-related symptom severity across the groups, with highest scores in patients with DID, followed by patients with PTSD, and the lowest scores for healthy controls. This supports the theory that there is an association between severity of trauma-related psychopathology and the age at onset, severity and intensity of traumatisation.
Dr Simone Reinders from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King's College London, said: 'Our findings correspond with research in other areas of psychology and psychiatry, which increasingly implicate trauma with mental health disorders such as psychosis, depression and now, dissociative identity disorder.
'We hope these insights into the causes and nature of DID will inform, among others, clinicians and forensic experts regarding differences between simulated and genuine DID.
'Ultimately this would lead to faster diagnosis and treatment for patients and greater recognition of DID as a mental health disorder.'
Dr Reinders added: 'We now want to understand the neurobiological underpinnings of DID and whether psychological or pharmacological therapies are more effective in treating the disorder.'
This research was funded by the Netherlands Organization for Scientific Research (http://www.nwo.nl), NWO-VENI grant no. 451-07-009.
Acta Psychiatrica Scandinavica