Bipolar disorder is common in depressed primary care patients

To examine the prevalence and treatment of typical and subsyndromal bipolar disorder (BD) in depressed primary care patients.

Patients with a diagnosis of a mood disorder being treated with antidepressants in 2 academic family practice clinics underwent a structured diagnostic interview (Mini International Neuropsychiatric Inventory) for manic and hypomanic symptoms.

Of 58 patients evaluated, 19% met full criteria for bipolar I disorder and 8.6% for bipolar II disorder; 31% had subsyndromal BD (ie, persistent elation or irritability accompanied by additional symptoms of hypomania but not enough symptoms to meet full criteria for bipolar I or II disorder). Only 5 patients with BD were receiving mood stabilizers, which had not been instituted in any patient by the primary care physician.

The high prevalence of patients meeting full criteria for BD and the low rate of identification of BD in primary care patients are consistent with estimates using self-administered questionnaires, but the interview revealed a substantial additional population that could be considered to have subsyndromal BD. Because subsyndromal forms of BD are associated with significant impairment and comorbidity as well as progression to frank BD, recognition of both full and subthreshold BD in primary care practice should be improved.