Three groups of mentally disordered offenders were identified in the cohort: 83 offenders with a substance abuse history, 540 with a psychiatric history, and 141 with a combined substance abuse and psychiatric history. A sample of 544 violent offenders with no mental health background was used a comparison group. Findings showed that offenders with mental health backgrounds, especially substance abusers, had more extensive criminal careers than other offenders. Former psychiatric patients were more frequently arrested for assaultive crimes; disturbed drug addicts were more frequently arrested for burglary and drug offenses; and alcoholic offenders were more likely to be involved in DUI, arson, assault, and reckless endangerment. These differences were mirrored in conviction offenses. Felony-related violence was less characteristic of offenders with mental health backgrounds than of other inmates, while offenders with psychiatric histories were more prone to unmotivated violence and sexual assault. The evidence suggests that serious emotional disorder was associated with an increased propensity to violent crime; recency of emotional disorder was related to greater levels of crime. Chapter references