Poor prophylactic lithium response due to antidepressants.

50 manic-depressive patients with rapid cycles received lithium for more than 1 year, during depression they received antidepressant drugs. Response was poor in 36, partial in 6, and good in 8. 21 of the poor responders were persuaded to endure depression without antidepressants; anxiolytics were allowed, 15 stabilized after the end of the untreated depression or after a few milder, shorter episodes; 4 improved partially; 2 were unchanged. 15 other rapid cycle patients started on lithium and stopped antidepressants at the same time. Response was good in 13, partial in 1, and poor in 1. Patients with a course of depression-hypomania (or mania)-free interval also responded poorly to prophylactic lithium when the depression was treated with antidepressants. They responded well when antidepressants were withdrawn. Antidepressants often cause or accentuate a switch from depression to hypomania or mania, and temporary refractoriness to lithium of the hypomania or mania. In this way lithium fails to prevent depression.