Mental Illness and Crime

Mental Illness as a Criminogenic Risk Factor

People have assumed for quite some time that there is a link between mental illness and crime. This is documented through decades of public opinion research. Historically, empirical findings have been mixed, with some studies showing no relationship and others showing a small significant correlation. Upon review of the research, it seems that little to no empirical relationship was documented between mental illness and crime or violence until the 1990s. A variety of researchers have since examined this issue in more detail, and most research does support a relationship between mental illness and criminal behavior or violence. Many believe that the results were mixed for so long due to methodological issues with the research that have since been able to be addressed. This section addresses some of the research with regard to the empirical relationship between mental illness and crime, as well as explores some of the theoretical implications of this relationship.

James Bonta, Moira Law, and Karl Hanson conducted a meta-analysis that focused on mentally disordered offenders. These are offenders that suffer from a mental illness and that engaged in some type of behavior that triggered the involvement of the criminal justice system. Bonta et al. examined several individual risk factors for both general and violent recidivism among mentally disordered offenders. With regard to general recidivism, they found that psychosis had effect sizes ranging from ‒.03 to .06, mood disorders had effect sizes that ranged from ‒.09 to .01, and antisocial personality disorder had effect sizes that ranged from .11 to .19. The results were similar for violent recidivism, where effect sizes for psychosis ranged from ‒.07 to ‒.01, mood disorders effect sizes ranged from ‒.04 to .06, and antisocial personality disorder effect sizes ranged from .13 to .23. While the effects of psychosis and mood disorders were not found to be statistically significant for either general or violent recidivism, antisocial personality disorder was a robust predictor in both [Page 607]categories. This finding is not surprising when examining the literature with regard to individual risk factors for crime. Don Andrews and Bonta consider antisocial personality disorder to be one of the Big Four predictors of criminal behavior. Bonta et al. also compared the results from this study featuring mentally disordered offenders to another study for nondisordered offenders and found that the results were nearly identical. This held for both general and violent recidivism.

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