- Published: November 18, 2012
Researchers and clinicians have long debated the legitimacy of Dissociative Identity Disorder (DID), more commonly known as Multiple Personality Disorder. One side states that DID results from severe childhood trauma and is associated with Post Traumatic Stress Disorder, while the other suggests that it is merely a result of psychotherapy – that psychologists legitimize it and reinforce the patient’s behavior through differential reinforcement.
Very little is known about the neural causes of these personality switches, though the hippocampus of people with DID is typically smaller than those without. While researching the subject, I found an interesting article in which an fMRI was used to detect changes in the brain while the subject underwent personality changes. It was found that while switching from the native personality to the alter personality, inhibition occurred bilaterally in the hippocampus, on the right side of the parahippocampal and medial temporal regions, and in small regions of the substantia nigra and globus pallidus. In contrast, when switching from the alter personality back to the native personality, the only change in brain function was activation in the right hippocampus. In addition, it was found that personality changes took around 30 seconds to fully complete.
People with DID present an interesting challenge to the courts. If multiple personalities know about a crime, should they all be tried? If all of the personalities are sane, should the person be considered sane or insane? In 1978, a serial rapist with DID was declared insane, and therefore not culpable of his crimes, because he lacked “one integrated personality”. However, just two years later, a defendant with DID who was charged with murdering his father was found guilty. The court stated that having alter personalities was not necessarily a mental disease that would preclude responsibility for murder. These examples show the extent to which courts vary in respect to DID.
I think there needs to be a standard in place for dealing with these types of cases so that it doesn’t vary by jurisdiction. I don’t think that merely having DID makes you less culpable of a crime by reason of insanity; instead, I think it depends on the mindset of the personality at time of the crime. However, I think that we need a much better understanding of the neurological mechanism behind DID before major court guidelines can be put in place.
For more information:
- NY Times Article: http://www.nytimes.com/1994/05/09/nyregion/multiple-personality-cases-perplex-legal-system.html?pagewanted=all&src=pm
- fMRI Scholarly Article: Tsai, Guochuan, Donald Condie, Ming-Ting Wue, and I-Wen Change. "Functional Magnetic Resonance Imaging of Personality Switches in a Woman with Dissociative Identity Disorders." Harvard Review of Psychiatry 7 (1999): 119-22. Web.
- Youtube Documentary: http://www.youtube.com/watch?v=B0LNyXsErb8