What is the relationship between mental illness, criminal conduct, and violence among individuals who come into contact with the law?

Mental Health Court

What is the relationship between mental illness, criminal conduct, and violence among individuals who come into contact with the law?

  • Among the general community, those with mental illness are more likely to end up in the criminal justice system than people without a mental illness.
  • For the most part, persons with mental illness become involved in the criminal justice system for the same reasons that persons without major illness do.
  • Although mental illness may be relevant to violence risk, this linkage is often over-reported and its causal roles are complex and likely rooted in individual and situational cofactors.
  • Active substance use among individuals with MI has been associated with higher criminal recidivism (which may or may not include violent crimes) across multiple studies.

There is a large body of research to suggest that many offenders experience mental health problems; yet the relationship between mental illness and criminal offending is notably complex. The relationship of violence and mental illness has been studied separately and is equally complex. Perhaps the most empirically rigorous study to address this question was the MacArthur Violence Risk Assessment Study (Monahan et al., 2001). These authors found that major mental illness was largely unrelated (and sometimes slightly negatively related) to violence. However, a co-occurring substance use disorder significantly increased the risk of violence in persons with mental illness. Additional findings and conclusions from this study can be found at www.macarthur.virginia.edu.

Empirical studies also suggest that the majority of variables predicting criminal recidivism in persons with mental illness tend to be the same variables found in persons without mental illness. For example, results of a large-scale meta-analysis by Bonta, Law, and Hanson (1998) looked at multiple factors that might be related to risk (e.g., clinical factors, deviant lifestyle factors, criminal history variables, and personal or demographic variables), and concluded that the strongest predictors for both populations included historical and demographic variables. Thus, MHC interventions that address criminogenic risk factors (e.g., substance use, criminal attitudes, criminal associates) in addition to psychiatric needs (e.g., medication adherence) may prove most efficacious in terms of reducing criminal behavior and mental health symptomatology.


Douglas, K.S., Guy, Laura, S., Hart, & Hart, S.D. (2009). Psychosis as a risk factor for violence to others: A meta-analysis. Psychological Bulletin, 35, 679-706.

Monahan, J., Steadman, H., Silver, E., Appelbaum, P., Robbins, P., Mulvey, E., et al. (2001). Rethinking risk assessment: The MacArthur Study of Mental Disorder and Violence. New York, NY: Oxford University Press.

Bonta, J., Law, M., & Hanson, K. (1998). The prediction of criminal and violent recidivism among mentally disordered offenders: a meta-analysis. Psychological Bulletin, 123, 123-142.