Comorbid bipolar disorder and borderline personality disorder and history of suicide attempts.

Both bipolar disorder and borderline personality disorder are associated with elevated rates of attempted suicide; however, no studies have examined whether there is an independent, additive risk for suicide attempts in patients diagnosed with both disorders. In the present study from the Rhode Island Methods to Improve Diagnostic Assessment and Services (MIDAS) project, 3,465 psychiatric outpatients were interviewed with semistructured interviews. Compared to the bipolar patients without borderline personality disorder, the patients diagnosed with both bipolar and borderline personality disorder were significantly more likely to have made a prior suicide attempt. The patients with borderline personality disorder and bipolar disorder were nonsignificantly more likely than the borderline patients without bipolar disorder to have made a prior suicide attempt. Bipolar disorder and borderline personality disorder were each associated with an increased rate of suicide attempts. The co-occurrence of these disorders conferred an additive risk, although the influence of borderline personality disorder was greater than that of bipolar disorder.