Since compliance is a major problem in the management of schizophrenia, we are developing a rapid simplified test to measure RIS and 9-OH-RIS in salive and compare the concentration in samples of plasma collected concurrently. In this study, 12 adult patients (18 years and above) or minors (aged 5 to 17 years) already taking risperidone for clinical reasons will take their usual morning dose. Risperidone is usually administered once or twice a day.