ABSTRACT
OBJECTIVE: The primary aim of this study was to compare electronic monitoring with other measures of adherence to Osmotic-controlled Release Oral delivery System methylphenidate in children with attention-deficit hyperactivity disorder (ADHD). The secondary aim was to analyze the relationships between adherence and clinical factors, including ADHD symptoms. METHODS: Thirty-nine children diagnosed with ADHD were monitored for adherence to medication over the course of eight weeks. Medication adherence was assessed using the Medication Event Monitoring System (MEMS), which is a bottle cap with a microprocessor that records all instances and times that the bottle is opened; patient self-report; clinician rating; and pill count. Information, including demographic and clinical characteristics, symptom rating scale, and psychological test results, were also collected. The relationships between adherence and clinical factors, including ADHD rating scores of baseline and of the changes, were assessed. RESULTS: The rate of non-adherence measured by the MEMS was found to be 46.2%, which was considerably higher than those of the patient self-report (17.9%), clinician rating (31.7%), and pill count (12.8%) of non-adherence. The rate of adherence measured by the MEMS was not significantly associated with baseline symptom severity or symptom changes over the eight weeks, although non-adherent group showed more severe baseline symptoms and inferior improvement. CONCLUSION: Adherence as measured by the MEMS showed a discrepancy with other measures of adherence in patients with ADHD. The symptom severity and level of improvement were not related to adherence with MEMS. Further studies are needed to evaluate the variables that may impact medication adherence in children with ADHD.