Basic research into the aetiology, physiology and psychopathology of schizophrenia can usually be applied to schizophrenic illnesses wherever they may occur. Each mental hospital however is unique in the area which it serves, the class of patient admitted, and the treatment services and social atmosphere it provides. This means that the results of research projects concerned with the treatment for schizophrenia cannot be transferred so readily from one hospital to another. Hospitals treating different groups of patients in a different social atmosphere can produce widely differing results. To some extent therefore each hospital has to determine its own treatment policy, which will be dependent upon its own particular problems and facilities.