 The vast majority of operations have been carried out on young and middle-aged adults, although some older people and, in the past, a very small number of children and teenagers have been operated on.Nowadays the operation is used in the treatment of depression, anxiety and obsessive–compulsive disorder.In the past it was also used in the treatment of schizophrenia and a wide variety of other disorders; some patients had been in a mental hospital for years before operation, others only briefly or not at all.