Bundy underwent multiple psychiatric examinations; the experts' conclusions varied. Dorothy Otnow Lewis, Professor of Psychiatry at the New York University School of Medicine and an authority on violent behavior, initially made a diagnosis of bipolar disorder, but later changed her impression more than once.
She also suggested the possibility of a multiple personality disorder, based on behaviors described in interviews and court testimony: a great-aunt witnessed an episode during which Bundy "seemed to turn into another, unrecognizable person ... [she] suddenly, inexplicably found herself afraid of her favorite nephew as they waited together at a dusk-darkened train station. He had turned into a stranger." Lewis recounted a prison official in Tallahassee describing a similar transformation: "He said, 'He became weird on me.' He did a metamorphosis, a body and facial change, and he felt there was almost an odor emitting from him. He said, 'Almost a complete change of personality ... that was the day I was afraid of him.'"