Bipolarity: The iceberg of affective disorders?

The higher than usual ratio of bipolar (48%) compared to unipolar (52%) illness found in the Amish study gives preliminary evidence that a considerable amount of hypomania and mania may have been missed in many studies of the affective spectrum. Like the proverbial iceberg, this submerged bipolarity is no less significant. To gauge the depth, duration, and clinical characteristics of the affective iceberg will require better research into the course of the illness, particularly during the nonhospitalized phase, and closer attention to possible contamination of unipolar samples. To be alert to the dangers of hidden bipolarity will open new clinical opportunities for improved treatment of these patients.