Tools to improve differential diagnosis of bipolar disorder in primary care.

Among patients seen in a primary care setting for depressive and/or anxiety symptoms, 20% to 30% are estimated to have bipolar disorder. Although relatively common in primary care settings, bipolar disorder is still underrecognized, primarily due to misdiagnosis as unipolar depression. Patients often seek treatment when they are depressed but uncommonly present with mania or hypomania, the specific markers of bipolar spectrum disorders. An awareness of the prevalence, characteristics, and predictors of bipolar disorder can help the primary care physician to properly differentiate between bipolar depression and unipolar depression. Completing a differential diagnosis of bipolar disorder requires obtaining a comprehensive patient history that investigates symptom phenomenology and associated features, family history, longitudinal course of illness, and prior treatment response. In addition to the clinical interview, the Mood Disorder Questionnaire and the World Health Organization Composite International Diagnostic Interview 3.0 can be useful tools for evaluating patients for bipolar disorder. Screening patients at risk for bipolar disorder will help to avoid the use of unproductive or possibly even harmful treatments.