A comparison of unipolar and bipolar depressive illness.

In a study of 40 consecutively hospitalized patients with research diagnoses of endogenous depression, the authors found no difference between unipolar and bipolar depressive patients in the risk for affective disorder in first-degree relatives, proportion of EEG or neuropsychological abnormalities, clinical evidence of the depressive syndrome, or response to doctor's choice of treatment. Bipolar patients had an earlier age of onset and displayed more manic symptoms that did unipolar patients. The authors conclude that the two forms of depressive illness are clinically and genetically homogeneous, are without identifying EEG or cognitive differences, and have an equally good response to somatic treatments.