Treatment of psychosis or other mental disorder s by means of brain surgery.
The first such technique was the prefrontal lobotomy . Fairly common from the 1930s through the 1950s, lobotomy reduced neurotic symptoms such as agitation and aggressiveness but also left patients apathetic and with a limited range of emotions; it has since been largely replaced by the use of tranquilizing and antipsychotic drugs (see psychopharmacology ). A form of psychosurgery developed more recently involves the placement of tiny lesions in specific areas of the brain and has little effect on intellectual function or quality of life; it has been used to treat obsessive-compulsive disorder and occasionally cases of severe psychosis.