Dietz P E
School of Medicine, University of California, Los Angeles.
Psychiatr Clin North Am. 1992 Sep;15(3):539-51.
Five patterns among mentally disordered offenders are distinguished by the relationship between mental disorder, on the one hand, and criminality, on the other. Pattern 1 offenders are those for whom crime is a response to psychotic symptoms, most often delusions or hallucinations. Pattern 2 offenders commit crimes motivated by compulsive desires, such as sex offenses by paraphiles and offenses regarded as evidence of disorders of impulse control. Pattern 3 offenders are those with personality disorder for whom the crime is merely one example of a maladaptive pattern of voluntary and knowing behavior. Pattern 4 offenders have coincidental mental illness that is unrelated to the crime. Pattern 5 offenders are those who become mentally disordered or feign mental disorder as a result of their crimes, such as those who dissociate upon seeing what they have done, those who become depressed in prison, those who become psychotic on death row, and those who malinger mental illness. Although these categories do not determine whether offenders are responsible for their behavior, some unknown proportion of Pattern 1 offenders do meet legal criteria for insanity, depending on the facts of each case and the applicable legal standards. It is arguable whether or not Pattern 2 offenders ever meet legal criteria of insanity. Offenders evidencing only Patterns 3, 4, or 5 are not candidates for an insanity defense.
