Formerly called multiple personality disorder, dissociative identity disorder (DID) is a controversial diagnosis that challenges forensic psychiatrists, other mental health clinicians, legal professionals, the media, and the public. DID cases often present in the criminal justice system rather than in the mental health system, and the illness perplexes experts in both professions.
Individuals may commit criminal acts while in a dissociated state….Defendants occasionally use DID as a basis for pleading not guilty by reason of insanity (NGRI). Controversy over the DID diagnosis has contributed to debates about the disorder’s role in criminal responsibility.
Theoretically, harm by a trusted caregiver forces a child to split off awareness and memory of the trauma to survive in the relationship.
The legal approach used by the defense in cases of NGRI due to DID will be determined by the jurisdiction in which the case is tried. The “Alter-in-control” approach considers the key issue as which “alter” (personality) was in control at the time of the offense and whether he or she met the insanity standard, the “Each-alter” approach considers whether each personality met the insanity standard, and the “Host-alter” approach considers whether the dominant or primary personality met the insanity standard.9
retrieved, 08-07-14 full article dissociative-identity-disorder-no-excuse-for-criminal-activity