1. A folow-up study of 30 cases of prefrontal lobotomy was done. Twenty-three of these patients were operated on after admission to St. Elizabeths Hospital after a prolonged incapacitating illness. Of these 23, 21 were benefited by the operation, 11 were considered social recoveries, and 9 were discharged from the hospital. An organic syndrome was substituted for the psychosis. Restitution of the patient's pre-psychotic state should not be expected. One patient was made worse.2. Protracted illness did not militate against improvement in these selected cases.3. The criteria employed for the selection of these cases for psycho-surgery are justified by the high percentage of patients that were benefited.4. No objective neurological signs resulted from the operation.5. Post-operative convulsions occurred in 10 out of 30 cases.6. Electroencephalograms of 23 out of 24 cases showed definite abnormalities.7. There is no correlation between EEG pattern and post-lobotomy improvement.Abstract Teaser