Basal and stimulated (0.2 mg TRH, 0.025 mg LHRH) levels of prolactin, TSH, and LH were measured in serum of 12 male and 10 female chronic schizophrenic patients, hospitalized and treated with neuroleptics from 6 to 21 years. The mean values of the three pituitary hormones were within the normal range in both sexes. Tolerance to the prolactin-increasing effect appears to be developed after long-term neuroleptic treatment; TSH and LH secretion are not markedly impaired. The severity of psychopathological syndromes failed to correlate with serum levels of prolactin, TSH, and LH.
