Forty-three patients received an open prefrontal leucotomy for severe and intractable psychiatric illnesses. As a result of the operation three patients died, three developed personality changes and one had repeated grand-mal seizures. Of the 40 patients followed up for six months, 57-5% showed marked improvement in their clinical state and 30-0% mild to moderate degrees of improvement whilst no patient's condition was considered to be worse. Significant improvement was obtained after operation in the mean scores on the Hamilton Anxiety Scale, the Hamilton Depression Scale, the Beck Depression Scale and the Neuroticism Scale of the Eysenck Personality Inventory. Extroversion, as measured by the Eysenck Personality Inventory, was significantly increased after operation. It is recommended that open prefrontal leucotomy procedures be replaced by the safer stereotactic or electrode implantation techniques and that all psychosurgery be confined to specialist units.