• homicide;
  • schizophrenia;
  • major depressive disorder;
  • bipolar disorder;
  • delusional disorder;
  • alcoholism

Objective:  This study was designed to investigate the association between major mental disorders (MMDs) and homicide.

Method:  The rates of exculpations because of MMDs among 1087 Austrian homicide offenders during 1975 and 1999 were compared with the rates of the respective disorders in the general population.

Results:  MMDs were associated with an increased likelihood of homicide (two-fold in men and six-fold in women). This was exclusively because of schizophrenia (age-adjusted ORs in men 5.85, CI 4.29–8.01; in women 18.38, CI 11.24–31.55) and delusional disorder in men (OR 5.98, CI 1.91–16.51). Comorbid alcohol abuse/dependence (additionally) increased the odds in schizophrenia, major depression and bipolar disorder.

Conclusion:  The increased likelihood of homicide in subjects with MMDs cannot be fully explained by comorbid alcoholism. The results point to the special importance of sufficient treatment for a subgroup of mentally ill individuals being at higher risk of violence.