Multiple personality disorder: diagnosis after a traumatic brain injury

A patient is described with memory deficits after a traumatic brain injury; she was eventually diagnosed as having multiple personality disorder. A delay in diagnosis of multiple personality occurred because her cognitive deficits were thought to be secondary to the traumatic brain injury. Neuropsychologic tests were not helpful in establishing the diagnosis. Her EEG was negative, and she had no clinical evidence of complex partial seizures, which have been described in association with this disorder. Only after a process of careful history taking and the establishment of a therapeutic alliance with the patient was the diagnosis established. This case highlights the necessity to consider a "differential diagnosis for amnesia" in all patients with traumatic brain injury. In some patients, both organic and psychogenic causes are discovered.