Mianserin in the prophylactic treatment of bipolar affective illness.

Mianserin in a dosage of 20 mg 3 times daily, was given to 13 patients with bipolar affective illness, who were previously maintained on lithium. 3 patients left the trial at their own request within a few days due to drowsiness in 2 cases and insomnia in the third. Of the remaining 10 patients, 6 became manic within the 3-month trial period. This result indicates that mianserin may be capable of precipitating mania in susceptible subjects with bipolar affective illness. This may be a general property of antidepressants, since it has been previously described with other groups of antidepressants.