Objective: The purpose of this study was to investigate factors for pharmacotherapy adherence in patients with attention-deficit/hyperactivity disorder (ADHD), with an emphasis on medication possession ratio (MPR).
Methods: The medical records of 300 clinic-treated youth diagnosed with ADHD were retrospectively reviewed. Patients from March 2005 through January 2009 were diagnosed using the Diagnostic and Statistical Manual of Mental Disorders, 4(th) ed., Text Revision (DSM-IV-TR) and psychological tests. Patients were classified based on the time period from the initial visit to the last visit. We selectively compared the early dropout group within 6 months and the long-term medication group over 36 months (LMed) to identify long-term follow-up characteristics. The short-term follow-up group was divided into an early dropout group without pharmacotherapy commencement (EDO) and a short-term medication group (SMed). Sociodemographic data, psychological test scores, and average MPR of the EDO, SMed, and LMed groups were compared.
Results: The number of EDO patients was 69 (23.0%) out of the 300 total patients who were studied, and there were 59 SMed patients (19.3%), and 60 LMed patients (20.0%). Compared with other groups, the EDO group included significantly more younger patients, younger parents, higher maternal education level, lower Short Form Korean-Conners' Parent Rating Scale (K-CPRS) score, and higher full scale and performance intelligence quotient (IQ). There was no significant correlation between the average MPR and the treatment duration.
Conclusions: Within the first 6 months of visiting the hospital, >40% of the patients dropped out of treatment regardless of methylphenidate (MPH) use. Twenty percent of the subjects showed adherence to MPH medication after 36 months.