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Suicide risk in bipolar patients: the role of co-morbid substance use disorders


Corresponding author: Dr James L. Kennedy, Head, Neuroscience Section, Center for Addiction and Mental Health, University of Toronto, 250 College Street, Toronto, ON, M5T 1R8, Canada. Fax: 416 979 4666; e-mail:


Objective:  Bipolar disorder is associated with a high frequency of both completed suicides and suicide attempts. The primary aim of this study was to identify clinical predictors of suicide attempts in subjects with bipolar disorder.

Methods:  We studied 336 subjects with a diagnosis of bipolar I, bipolar II, or schizoaffective disorder (bipolar type). The Structured Clinical Interview for DSM-IV (SCID-I) was administered and subsequently two expert psychiatrists established a diagnosis. Predictors of suicide attempts were examined in attempters and non-attempters.

Results:  The lifetime rate of suicide attempts for the entire sample was 25.6%. A lifetime co-morbid substance use disorder was a significant predictor of suicide attempts: bipolar subjects with co-morbid substance use disorders (SUD) had a 39.5% lifetime rate of attempted suicide, while those without had a 23.8% rate (odds ratio=2.09, 95% CI=1.03–4.21, χ2=4.33, df=1, p=0.037).

Conclusions:  Lifetime co-morbid SUD were associated with a higher rate of suicide attempts in patients with bipolar disorder. This relationship may have a genetic origin and/or be explained by severity of illness and trait impulsivity.