The Relationship Between Symptomatic and Functional Changes of Korean Children and Adolescents With Attention-Deficit/Hyperactivity Disorder Treated With Osmotic-Controlled Release Oral Delivery System-Methylphenidate

Objectives: This study examined the effect of osmotic-controlled release oral delivery system-methylphenidate (OROS-MPH) on the adaptive functioning of children and adolescents with attention-deficit/hyperactivity disorder (ADHD) and investigated the relationship between reduced ADHD symptoms and improvements in functioning and factors that are predictive of functional improvement. Methods: This study was a prospective, multicenter, open-label study of 116 children with ADHD treated with OROS-MPH for 12 weeks. Attention-deficit/hyperactivity disorder symptoms, functional impairment, and other comorbid disorders were evaluated using various clinical scales. Correlational and multiple regression analyses were conducted to examine the relationship between symptomatic versus functional changes after OROS-MPH treatment. Results: Correlation analysis showed a moderately strong association between changes in the ADHD core symptoms versus functional measure scores (r = -0.65). The self-control subscale of the Life Participation Scale showed higher correlations with symptomatic measures than did the happy/social subscale. Functional outcomes were impacted by several factors including the baseline severity of ADHD symptoms, changes in ADHD, and oppositional defiant symptoms after treatment. Attention was more associated with functional outcomes than hyperactivity/impulsivity. Conclusions: Treatment with OROS-MPH was associated with symptomatic functional changes that were moderately correlated; therefore, symptomatic functional outcomes appear to be partially overlapped but distinct domains. Consequently, functional measures should be incorporated as important outcome measures in future treatment studies; the importance of treatments targeting functional improvement should be emphasized in the treatment of children with ADHD.