BACKGROUND A relationship exists between mental disorder and offending behaviours but the nature and extent of the association remains in doubt.
METHOD Those convicted in the higher courts of Victoria between 1993 and 1995 had their psychiatric history explored by case linkage to a register listing virtually all contacts with the public psychiatric services.
RESULTS Prior psychiatric contact was found in 25% of offenders, but the personality disorder and substance misuse accounted for much of this relationship. Schizophrenia and affective disorders were also over-represented, particularly those with coexisting substance misuse.
CONCLUSIONS The increased offending in schizophrenia and affective illness is modest and may often be mediated by coexisting substance misuse. The risk of a serious crime being committed by someone with a major mental illness is small and does not justify subjecting them, as a group, to either increased institutional containment or greater coercion.