The purpose of this research is to: (1) examine the secrection of risperidone (RIS) (Risperdal) and its metabolite, 9-OH-RIS, in saliva, (2) determine the concentration ratio of RIS and 9-OH-RIS between plasma and saliva, and (3) compare the rate of decline in concentration of RIS and 9-OH-RIS in saliva and plasma by measurements at timed intervals during a single dosing interval.