The treatment of 198 psychiatrically disabled patients with stereotactic cingulotomy was evaluated prospectively for a mean follow-up of 8.6 years. Patients with major affective disorders and anxiety disorders fared the best, with a return to normal functioning in the majority. Patients with obsessive-compulsive disorders, schizophrenia, and personality disorders improved less predictably, with an uneven improvement in functioning that required active ongoing psychiatric treatment. Low mortality and morbidity, a reduction of violent behavior, a possible reduction of suicidal risk, and a lessening of the intractable suffering of chronic psychiatric illness all indicate that cingulotomy can be an effective, safe treatment for patients with affective disorders that are unresponsive to all other forms of therapy.