The finding suggests mental illness tends to lead to deviant behavior rather than violent behavior; mental illness is a causal factor in deviant behavior, some of which involves violence, and that the more deviant the behavior, the greater the effect of mental illness. Among incarcerated offenders, mental health problems were more strongly associated with assaultive violence and sexual offenses than many other types of crime; violent offenders were more likely to receive treatment after they committed the offense but before incarceration. In examining whether offenses committed by people with mental health problems tend to be particularly anti-normative, it was found that all of the offenses involved anti-normative behavior, however, some were more deviant than others. Mental health problems played a greater role in sexual offenses and physical assaults. Regarding gender, men who assaulted or killed men (the most common type of violence assault) were least likely to have mental health problems. Women who committed assaultive violence were more likely to have mental health problems than men who committed these offenses. The gender difference in major mental health problems was stronger for assault and property crimes, suggesting that gender differences in mental illness and treatment could not fully explain the higher rate of mental health problems observed among female assault offenders. The results provide some supportive evidence that mental illness plays a greater role in the violence of female offenders than male offenders. Women who assaulted men were more likely to have mental health problems than women who assaulted other women. Older violent offenders were no more likely to have mental health problems than younger offenders, even though violence is less normative among older offenders. Data were collected from the Survey of Inmates in State and Federal Correctional Facilities, 1997, a nationally representative sample of inmates from State and Federal facilities. Tables, figure, notes, and references