Serious Mental Illness and Sexual Offending in Forensic Psychiatric Patients.

Abstract

The role of serious mental illness among those who sexually offend is not well understood. We investigated clinical and risk-related areas of difference between male forensic psychiatric patients with (n = 86) and without (n = 245) a sexual offense history, including the age at which indications of mental disorder and criminal offending first emerged, from a registry of Ontario patients adjudicated Not Criminally Responsible on account of Mental Disorder (NCRMD) from 1999-2012. We further explored motivations for offending among a subset of patients deemed NCRMD for a sexual offense specifically (n = 41). While no differences were found in the age onset of illness or offending across those with and without a sexual offending history, the former group was rated as having higher levels of historical/static risk for violence. Forensic patients with a sexual offense history were also more likely to offend against a stranger, and less likely to offend against a family member. Sexual index offenses were psychotically-motivated in the majority of cases, but with a meaningful proportion appearing to reflect criminogenic motivations, especially substance use and paraphilic interests. Results suggest greater similarity than difference among forensic patients with and without a sexual offense history, but also highlight an important divergence from the literature showing that victims of sexual offenses are frequently known to the individual committing them.