reasonable doubt. >> professor richard bonnie is an expert on law and psychiatry. he wrote what is considered a definitive textbook on the hinckley trial. >> as far as the prosecution was concerned, the dominant diagnosis was that this was a person with a narcissistic personality disorder that was infatuated with jodie foster, and basically what he really wanted was to be tame miscellaneous. but that he was in touch with reality. as far as the defense was concerned, that he basically had a form of schizophrenia, a schizophrenic process disorder, that he was out of touch with reality, was descending into psychosis, that he was delusional. >> my interpretation of insanity goes back to the old m'naghten rule. and it's very simply, can the individual differentiate right from wrong? and clearly during my interview with john hinckley, he clearly understood the difference