DIFFERENCES FOUND IN THE PROPORTIONS OF TYPES OF CRIMES FOR VARIOUS PSYCHIATRIC DIAGNOSES ARE NOT STRIKING. REFERRALS OF DEFENDANTS WITHOUT PSYCHIATRIC ILLNESS INVOLVE CRIMES AGAINST PERSONS TO A GREATER DEGREE THAN OTHER DIAGNOSTIC CATEGORIES, AND PROBABLY REFLECT CRITERIA FOR REFERRAL AND AN INDEX OF SUSPECTED PSYCHIATRIC DISORDER BY THOSE MAKING REFERRALS. AMONG PERSONS DIAGNOSED WITH SCHIZOPHRENIA, AFFECTIVE DISORDER, ORGANIC BRAIN DISORDER, AND MENTAL RETARDATION (DIAGNOSES WHICH MAY PROVIDE A BASIS FOR AN INSANITY PLEA), SCHIZOPHRENICS AND AFFECTIVE DISORDERED PERSONS ARE CHARGED WITH FEWER SEXUAL OFFENSES AND MORE OFFENSES AGAINST THE PUBLIC, WHILE THOSE WITH ORGANIC BRAIN SYNDROME OR MENTAL RETARDATION WERE MORE LIKELY TO BE CHARGED WITH SEXUAL OFFENSES. ABOUT ONE-FOURTH OF THE PATIENTS RECEIVED A SECONDARY DIAGNOSIS OF WHICH ALCOHOLISM AND DRUG ADDICTION WERE THE MOST COMMON. PERSONALITY DISORDER WAS THE SINGLE MOST COMMON DIAGNOSIS AMONG REFERRALS, AND SHOWED FAIRLY PROPORTIONAL DISTRIBUTION ACROSS CRIME CATEGORIES. SCHIZOPHRENICS WERE LEAST LIKELY TO BE CHARGED WITH FRAUD OR FORGERY, WHILE THIS WAS THE MOST COMMON CHARGE AMONG THE AFFECTIVE DISORDERED. MENTAL RETARDATES ARE MOST FREQUENTLY CHARGED WITH ARSON, WHILE PERSONALITY DISORDERED INDIVIDUALS ARE THE LEAST LIKELY TO BE SO CHARGED. THE CATEGORY OF THE 'OTHER DIAGNOSIS,' WHICH INCLUDED DIAGNOSED SEX DEVIANTS, CONTAINED THE MOST INDIVIDUALS CHARGED WITH SEXUAL OFFENSES. DEFENDANTS WITH NO PSYCHIATRIC ILLNESS ARE CHARGED MORE OFTEN WITH HOMICIDE, AND PERSONS WITH ORGANIC BRAIN SYNDROME ARE MORE LIKELY TO BE CHARGED WITH ASSAULT. IN GENERAL, NO SIGNIFICANT CORRELATIONS BETWEEN PSYCHIATRIC DIAGNOSIS AND TYPES OF CRIMINAL ACTIVITY WERE FOUND. RESULTS OF A NUMBER OF PREVIOUS STUDIES OF THE CORRELATION BETWEEN DIAGNOSIS AND TYPES OF OFFENSE ARE SUMMARIZED. ALTHOUGH PSYCHOSIS IS RELATIVELY RARE IN ASSOCIATION WITH SERIOUS CRIMINAL ACTIVITY, SUCH CASES ARE FOUND AND IN THESE EXCEPTIONS PSYCHIATRIC INPUT CAN HELP PREVENT THE FAILURE TO TREAT A TREATABLE GROUP OF DEFENDANTS. IT IS SUGGESTED THAT PSYCHIATRY'S ABILITY TO PREDICT DANGEROUSNESS OR TREATABILITY OR TO DETERMINE QUESTIONS OF CRIMINAL RESPONSIBILITY ARE LIMITED. WHAT PSYCHIATRY CAN OFFER IS THE BEST INFORMATION ON THE INFLUENCE OF VARIOUS MENTAL ILLNESSES ON BEHAVIOR, THE EXPECTED RESULTS OF TREATMENT, AND ADVOCACY OF THE PATIENT'S NEEDS CONSISTENT WITH A RESPONSIBLE VIEW OF SOCIETAL REQUIREMENTS. REFERENCES ARE INCLUDED. (JAP)