Risk factors for suicide in bipolar disorder: a cohort study of 12 850 patients

Abstract

Objective: Bipolar disorder carries a high risk of suicide. Identification of risk factors is important. The aim of this study was to study risk factors for suicide in a large cohort of men and women with bipolar disorder.

Method: A prospective cohort study using clinical data from the Swedish National Quality Register for Bipolar Affective Disorder (BipoläR). The outcome variable was suicide captured in the Cause of Death Register between 2004 and 2014. Hazard ratios (HR) were calculated using Cox proportional hazards models.

Results: Of 12 850 persons (4844 men and 8006 women) with bipolar disorder, 90 (55 men and 35 women) died by suicide during the follow-up period (between 1 and 10 years). Male sex (HR 2.56), living alone (HR 2.45), previous suicide attempts (HR 4.10), comorbid psychiatric disorder (HR 2.64), recent affective episodes (HR 2.39), criminal conviction (HR 4.43), psychiatric inpatient care (HR 2.79), and involuntary commitment (HR 3.50) were significant risk factors for suicide. Several of the statistically significant risk factors for suicide in bipolar disorder differed between men and women.

Conclusions: Risk factors for suicide in bipolar disorder include factors associated with suicide in general, but also diagnosis-specific factors.

Keywords: bipolar disorder; risk factors; suicide.