Several pharmacological stimulation tests of the pituitary-hypothalamic system have been used to investigate psychiatric disorders. This study introduces amphetamine sulfate as a stimulus for human growth hormone (HGH) release in various psychiatric patients. Peak HGH release after a single intravenous administration of amphetamine sulfate, 0.1 mg/kg, was significantly lower in nine "endogenous" depressives (P = .01) and significantly higher in seven "reactive" depressives (P less than .05) as compared to normal subjects, whereas peak HGH release in eight schizophrenics and six chronic alcoholics did not differ significantly from that in normal subjects.