Does co-morbid personality disorder increase the risk of suicidal behaviour in psychosis?

Objective: To examine the association between co-morbid personality disorder (PD) and suicidal behaviour over a 2-year period in a sample of patients with psychosis. Method: A total of 670 patients with established psychotic illness were interviewed using a battery of instruments including a screen for comorbid PD. The prevalence of attempted and completed suicide was measured over the next 2 years using multiple data sources. Logistic regression was used to examine whether those with co-morbid PD were at greater risk of suicidal behaviour compared with others. Results: One hundred and eighty six patients (28%) were rated as having a co-morbid PD. After adjusting for all covariates, patients with co-morbid PD were significantly more likely to attempt or complete suicide over the 2-year period (adjusted odds ratio: 1.87; 95% CI: 1.02-3.42). Conclusion: Co-morbid PD is independently associated with an increased risk of suicidal behaviour in psychosis. Early assessment of personality status should be part of the routine assessment of all psychiatric patients.