IntroductionAttention deficit hyperactivity disorder (ADHD) is the most commonly diagnosed psychiatric condition in childhood, which if untreated may have a negative effect on education, peer relationships and family disharmony. Methylphenidate is an effective treatment for ADHD, although its use is limited by poor compliance and side effects. Studies on effects of side effects on efficacy, and adherence of methylphenidate in developing countries are scarce. MethodsWe assessed the adherence, efficacy, and side effects of methylphenidate in children and adolescents treated at a child and adolescent psychiatry clinic of North Colombo Teaching Hospital, Ragama. We gathered information from guardians of the children treated with methylphenidate for at least 2 months, using an interviewer administered questionnaire. ResultsAmong the 149 participants, a majority were males and the mean age of the population was 10.4 years. More than 52% participants reported 100% compliance with methylphenidate, but only 12% complied with non-pharmacological therapies. While 75% believed the medication to be effective, only 17% perceived psychosocial strategies to be useful. Poor appetite (44%) was the most common side effect of methylphenidate and 43% did not report any side effect. There was a negative correlation between compliance with methylphenidate and the occurrence of poor appetite, as well as with not increasing the initial dose. DiscussionThe results of this study suggest that methylphenidate is an effective and well-tolerated treatment for children in Sri Lanka with ADHD.