In a study of patients treated biweekly with 25–50 mg of risperidone for 24 weeks, 5 cases (16 %) of prolactin-related adverse events, comprising 2 cases (6.5 %) of gynecomastia/galactorrhea and 3 cases (9.7 %) of amenorrhea/dysmenorrhea, were reported [30]. The gene discussed is PRL; the disease is amenorrhea.