Verapamil has been found in some but not all studies to have antimanic activity. Therefore, we investigated the use of verapamil, alone or as an adjunctive treatment, in manic patients who did not respond to an initial adequate trial of lithium. Each study phase lasted three weeks. Subjects were treated openly with lithium in Phase 1 (n=45). Those who failed to respond were randomly assigned to double-blind treatment in Phase 2 with either verapamil (n=10) or continued lithium (n=8). Phase 2 responders were continued on the same medication in Phase 3. Phase 2 nonresponders (n=10) were assigned to combined verapamil/lithium in Phase 3.