Criminal behaviour and violent crimes in former inpatients with affective disorder

Several studies have reported criminal and violent behaviour in people with schizophrenia but few have investigated the association between affective disorders and violent behaviour.

We reviewed the national crime register for records of criminal offences committed by 1561 patients with affective disorders treated between 1990 and 1995 in the Psychiatric Hospital of the University of Munich. The sample was divided into patients with bipolar I disorder, manic disorder and major depressive disorder. Sociodemographic and other risk factors for non-violent and violent criminal behaviour were analysed.

Sixty-five (4.16%) patients had been convicted in the 7 to 12 years after discharge (307 cases). The rate of criminal behaviour and violent crimes was highest in the manic disorder group: 15.7% (14 of 89) were listed in the national crime register and 5.6% (5 of 89) were convicted of physical injury offences. Violence and criminality were comparatively rare in patients with major depressive disorder: only 1.42% (10 of 702) committed violent crimes. Male gender was a substantial risk factor for non-violent and especially violent behaviour: the rate of violent crimes was six times higher than in females. Marital status appeared to influence the prevalence of later delinquency: separated, divorced and widowed patients committed offences more frequently. A history of substance use problems before clinical treatment was reported by 21.2% (329 of 1561) of the sample. A wide range of different crimes were committed, with defalcation, theft and fraud being the most frequent. Twenty-one cases of physical assault and one case of later homicide were recorded. In contrast to other forensic studies, we did not find a significant effect of substance abuse on the risk of later delinquent behaviour.

The frequency of criminal behaviour and violent crimes in individuals with affective disorder depends on much more than just the diagnosis. This study may stimulate further research to identify psychopathological predictors for future violent and criminal behaviour.