• Intravenously administered methylphenidate, 0.5 mg/kg, causes a consistent rise in human serum growth hormone level, with peak values usually occurring 30 minutes after infusion. This rise is attenuated in patients receiving various antipsychotic medications administered on a long-term basis and is decreased in schizophrenic and drug-dependent patients. Methylphenidate causes increases in talkativeness, blood pressure, and pulse that generally parallel increases in serum growth hormone level. However, in contrast to the methylphenidate-induced rise in serum growth hormone level, methylphenidate-induced changes in cardiovascular variables and talkativeness are not altered by antipsychotic medications or diagnostic classification.
Janowsky DS, Leichner P, Parker D, Judd LL, Huey L, Clopton P. The Effect of Methylphenidate on Serum Growth HormoneInfluence of Antipsychotic Drugs and Diagnosis. Arch Gen Psychiatry. 1978;35(11):1384-1389. doi:10.1001/archpsyc.1978.01770350110011