Background: The impact of comorbid personality disorder on the occurrence of violence in psychosis has not been fully explored.
Aims: To examine the association between comorbid personality disorder and violence in community-dwelling patients with psychosis.
Method: A total of 670 patients with established psychotic illness were screened for comorbid personality disorder. Physical assault was measured from multiple data sources over the subsequent 2 years. Logistic regression was used to assess whether the presence of comorbid personality disorder predicted violence in the sample.
Results: A total of 186 patients (28%) were rated as having a comorbid personality disorder. Patients with comorbid personality disorder were significantly more likely to behave violently over the 2-year period of the trial (adjusted odds ratio=1.71, 95% CI 1.05-2.79).
Conclusions: Comorbid personality disorder is independently associated with an increased risk of violent behaviour in psychosis.