This study focused on the effectiveness of nonphysicians in providing care for outpatients suffering from manic-depressive disease. All the patients were participating in a longitudinal study of the potential of lithium in preventing affective illness. The 20 patients studied had all been followed for the same 78-week period, during which they were seen and interviewed at least once a month by teams of psychiatric nurses and aides. The teams used a manic-depressive rating scale to detect symptoms that might need a physician's attention. Fourteen of the patients remained free of affective episodes and never required the services of a psychiatrist. The approach expanded the availability of psychiatric services without sacrificing effectiveness.