The patient was a 19-year-old woman with a history of schizophrenia taking thioridazine and valproic acid (dosages unspecified). Thioridazine was discontinued and prolactin was measured 2 weeks later. Valproic Acid was used as a monotherapy for some time, but psychiatric symptoms recurred, so it was replaced by clozapine and electroconvulsive therapy. The patient was switched to thiothixene but had a recurrence of hyperprolactinemia and other similar symptoms, so clozapine therapy was reinstated. The gene discussed is PRL; the disease is hyperprolactinemia.