Factors Affecting Delayed Initiation and Continuation of Medication Use for Attention-Deficit/Hyperactivity Disorder: A Nationwide Study

Objective: This study evaluated the predictors for delayed initiation and continuation of ADHD medication use in children and adolescents with ADHD in Taiwan. Methods: This longitudinal cohort study enrolled 188,061 children and adolescents with ADHD between 2001 and 2011. Delayed initiation of ADHD medications was defined as the interval >365 days between diagnosis and first prescription, and continuation of ADHD medications was defined as ≥365 defined daily doses of ADHD medications. Results: Of the included patients, 39.2% were never treated with ADHD medications. Delayed initiation and continuation of ADHD medication use were found in 11.9% and 19.9% of the ever-treated patients, respectively. Younger age at ADHD diagnosis, male sex, older mother's age at child's ADHD diagnosis, and higher family income were associated with more delayed initiation but were also associated with more continuation of ADHD medication use. Conclusions: The initiation and continuation of ADHD medication use might be underlined by different mechanisms and warrant different strategies.