Effects of risperidone on gonadal axis hormones in schizophrenia

To investigate the effects of risperidone on the hypothalamo-pituitary-gonadal (HPG) axis of chronic schizophrenic male inpatients medicated regularly.

Subjects included six inpatients who were diagnosed according to the Diagnostic and Statistical Manual, Fourth Edition, criteria for schizophrenia, and were termed treatment-refractory. Each patient gave informed consent for the research involved in this study. The neuroendocrine studies were done before and during risperidone administration. Patients took a mean dose of risperidone 9.5 mg/d for a mean period of 64.2 days. Psychotic symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS).

Prolactin (PRL) increased significantly during risperidone administration. However, luteinizing hormone, follicle-stimulating hormone, and testosterone did not show significant difference between blood concentrations before and during risperidone administration. Scores of the BPRS total, thought disturbance factor, and tension decreased significantly during risperidone administration. Throughout the study, none of the patients experienced clinically significant problems associated with elevated PRL concentrations including gynecomastia and/or sexual dysfunction.

Addition of risperidone produced significant improvement of psychotic symptoms in treatment-resistant schizophrenic patients, and an increase in basal blood PRL concentrations, but not in basal blood HPG axis hormone concentrations. This preliminary result warrants further double-blind evaluation with a larger sample.