Sex offenders and insanity: An examination of 42 individuals found not guilty by reason of insanity

Although currently there is a large body of research on the characteristics and treatment of sex offenders, very little research has been conducted to investigate the characteristics of sex offenders who have been adjudicated insane. This study included 42 patients at Napa State Hospital who were adjudicated not guilty by reason of insanity (NGRI) for a sex offense. The sample was further divided into offenders whose victims were children and those whose victims were adults. Data were collected with a structured chart review instrument. A large percentage of the sex offenders received a primary diagnosis of schizophrenia or schizoaffective disorder, and many had a comorbid substance use disorder. The high percentage of sex offenders in the current study with diagnosed schizophrenia or schizoaffective disorder may represent a previously unstudied subgroup of sex offenders. An alternative explanation is that the experts did not evaluate substance use and intoxication adequately, assess for malingering, or apply the proper legal standard for insanity.