Dopamine receptors and average clinical doses.

azines, butyrophenones, or thioxanthenes. Measurement of the effect of drugs of these classes on serum prolactin levels in the rat also serves to identify dopamine receptor blockers and is much simpler (10). Of greater importance is the fact that there are many drugs of these classes already in clinical use. New drugs of the same type usually differ only quantitatively in potency, sedative effects, and extrapyramidal side effects but do not increase the proportion of patients who will respond, the extent of improvement, or the rapidity of response. Vast numbers of schizophrenics are chronically impaired despite neuroleptic treatment. The real need is to develop entirely different chemical approaches to the prophylaxis and treatment of schizophrenia. HERBERT Y. MELTZER Department ofPsychiatry, Pritzker School ofMedicine, University of Chicago, Chicago, Illinois 60637, and Illinois State Psychiatric Institute, Chicago 60612