Clinical status of comorbid bipolar disorder and borderline personality disorder.

BACKGROUND The status and differentiation of comorbid borderline personality disorder and bipolar disorder is worthy of clarification. AIMS To determine whether comorbid borderline personality disorder and bipolar disorder are interdependent or independent conditions. METHOD We interviewed patients diagnosed with either a borderline personality disorder and/or a bipolar condition. RESULTS Analyses of participants grouped by DSM diagnoses established that those with comorbid conditions scored similarly to those with a borderline personality disorder alone on all key variables (i.e. gender, severity of borderline personality scores, developmental stressors, illness correlates, self-injurious behaviour rates) and differed from those with a bipolar disorder alone on nearly all non-bipolar item variables. Similar findings were returned for groups defined by clinical diagnoses. CONCLUSIONS Comorbid bipolar disorder and borderline personality disorder is consistent with the formal definition of comorbidity in that, while coterminous, individuals meeting such criteria have features of two independent conditions.