Medication Nonadherence in Children and Adolescents with ADHD.

Objective: Attention-deficit/hyperactivity disorder (ADHD) affects 6-10 % of children and adolescents worldwide. While psychopharmacological treatments effectively reduce symptoms, incomplete adherence is common, diminishing their effectiveness. This study investigated medication nonadherence and its predictors in children and adolescents with ADHD. Method: The TDM-VIGIL study, a multicenter prospective observational study in Germany, examined drug-related risks of ADHD medication in hyperkinetic disorders and nonadherence. Participants aged 6-18 years with ADHD (ICD-10/DSM-IV) starting stimulants or nonstimulants were assessed for nonadherence using the Medication Assessment Questionnaire (MAQ) at multiple time points. Patients were classified as fully or not fully adherent, and logistic regression analysis was used to identify predictors. Results: Among 198 participants (mean age = 10.4 years), 66.1 %-75.4 % were fully adherent across time points. Higher age and lower intelligence were significantly associated with nonadherence, while sex, disease severity, adverse events, treatment setting (outpatient, day clinic, inpatient), medication class (stimulant, nonstimulant), and treatment strategy (mono- versus polypharmacy) were not. Conclusions: Medication nonadherence is common in youth with ADHD, with higher age and lower intelligence representing relevant risk factors. Clinicians should consistently monitor adherence and address individual barriers.