Family physicians inevitably encounter patients with bipolar disorders, often when the patient is depressed. For most of these patients, the attendant elevations in mood fall short of mania. Such milder periods of expansive mood, hypomanias, may go unrecognized unless the physician specifically queries the patient to uncover them. In addition, patients with bipolar disorders often manifest other distinctive characteristics. An understanding of these hints of bipolarity is helpful to clinicians treating depressive illness. Patients with bipolar disorders are at risk for treatment complications caused by the administration of antidepressants without the concurrent use of mood stabilizers, such as lithium carbonate, valproate sodium, and carbamazepine. Such complications include exacerbation of hypomania or mania, induction of refractory states, and, perhaps, rapid cycling or mixed states. We review current issues in classification of bipolar disorders and emphasize the importance of identifying hypomania. An introduction to the concept of affective temperaments and a brief review of treatment strategies and treatment complications are included.