This was a randomized (the study drug is assigned by chance) and open labeled (all people know the identity of the intervention) study. All participants were hospitalized in research rooms and were subsequently restricted in exercise, eating, drinking, smoking and xanthine-beverages until the end of blood collection. Water was allowed to be taken until one hour before drug administration. Participants were randomly assigned into two groups, one group receiving Risperdal OD (investigational drug), and one group receiving Risperdal Quicklet (control drug). On the day of testing, blood was collected from all participants to provide baseline measurements. Subsequently, the study drug was orally administered to the participants, followed by blood collection of a total of 13 time points, up to 24 hours. After the blood collection was finished, participants were discharged after receiving proper guidance and being examined by a psychologist. Following a wash-out period (period when receiving no intervention) of one week, participants were hospitalized once more and crossed over to receive the study drugs following the same procedure above described. The approximate study duration (including the drug administration days and wash-out period) was approximately 10 days.