IT IS THE purpose of this report to describe a case of severe schizophrenia in which certain psychotic manifestations were greatly reduced by prefrontal lobotomy, despite the presence of advanced hydrocephalus. A search of the literature reveals no instance in which a patient with such extreme hydrocephalus has been subjected to lobotomy, and for this reason the case is believed to be unique.The Boston Psychopathic Hospital Group,1 on the basis of their review of the literature, concluded that, except for mental derangements appearing with epilepsy, psychoses associated with organic cerebral changes have generally not profited from lobotomy. These investigators described three of their own cases in which obsessive\x=req-\ compulsive features were relieved by the operation, although each patient had evidence of organic damage, as indicated by preoperative psychometric studies and by gross "cortical atrophy" noted at operation. Pneumoencephalographic studies were not performed. Their series also included 13 cases with signs or symptoms suggestive of brain damage secondary to meningitis, encephalitis, head injury, idiopathic cerebral atrophy, or convulsive seizures, and a "good mental status" resulted in only one of these cases.The experience of Freeman and Watts 2 led them to believe that organic brain disease is not a contraindication to lobotomy, although the results are not likely to be as good as in an uncomplicated psychosis because the increase in unrestrained behavior leads to difficulties in social adjustment. Included in their series were cases of Parkinsonism, Huntington's chorea, postencephalitic behavior disorder, epilepsy, cerebral thrombosis, birth palsy, familial spastic paraplegia, head injury, and multiple sclerosis.The series of Partridge 3 included six cases with organic features in which lobotomy was performed. Considerable improvement was obtained in a case of From the Divisions