This volume contains the proceedings of the fourth international symposium held in November 1970 at the Texas Research Institute of Mental Sciences in Houston. Leading psychiatrists, biochemists, and pharmacologists from the United States and Great Britain presented new material and reviewed current concepts concerning schizophrenia and the affective disorders, with particular reference to the neurochemical basis of the etiology and chemotherapy of these diseases. Although the multiple mechanisms of mental disease are still not fully understood, substantial progress has definitely been made....