This article reviews the epidemiological evidence that bipolar affective disorder is often underdiagnosed and hence ineffectively treated. In order to mitigate this problem, all patients with depression should be systematically assessed using a full longitudinal history in order to detect hypomanic symptoms, as well as a family history. This is expected to lead to more appropriate diagnosis, and consequently treatment, of bipolar affective disorder.
Keywords: bipolar affective disorder, unipolar depression, underdiagnosis, misdiagnosis