Neuroendocrine tests during treatment with neuroleptic drugs. II. The TRH test

Anterior pituitary response to TRH 200 micrograms i.v. was studied in ten chronic schizophrenic patients during long-term neuroleptic treatment. Nine patients had normal prolactin (PRL) response as compared with controls but in one the response was blunted; one patient had an exaggerated response. Prolactin increment was higher following TRH than haloperidol challenge. No growth hormone (GH) response to TRH was found and TSH responses were comparable to controls.