A case-linkage study of crime victimisation in schizophrenia-spectrum disorders over a period of deinstitutionalisation

Background: Despite high rates of self-reported crime victimisation, no study to date has compared official victimisation records of people with severe mental illness with a random community sample. Accordingly, this study sought to determine whether persons with schizophrenia-spectrum disorders have higher rates of recorded victimisation than the general population, and to explore whether there have been changes in rates of recorded victimisation over a period of deinstitutionalisation. Methods: The schizophrenia-spectrum cases were drawn from a state-wide public mental health register, comprising all persons first diagnosed with a schizophrenic illness in five year cohorts between 1975 - 2005. The criminal histories of 4,168 persons diagnosed with schizophrenic-spectrum disorders were compared to those of a randomly selected community sample of 4,641 individuals. Results: Compared to community controls, patients with schizophrenia-spectrum disorders were significantly more likely to have a record of violent (10.1% vs. 6.6%, odds ratio 1.4) and sexually violent victimisation (1.7% vs. 0.3%, odds ratio 2.77), but less likely to have an official record of victimisation overall (28.7% vs. 39.1%, odds ratio 0.5). Over the approximate period of deinstitutionalisation, the rate of recorded victimisation has more than doubled in schizophrenia-spectrum patients, but stayed relatively constant in the general community. Conclusions: People with schizophrenic-spectrum disorders are particularly vulnerable to violent crime victimisation; although co-morbid substance misuse and criminality both heighten the chances of victimisation, they cannot fully account for the increased rates. Deinstitutionalisation may have, in part, contributed to an unintended consequence of increasing rates of victimisation amongst the seriously mentally ill.