Predictive Factors for Persistent Use and Compliance of Immediate-Release Methylphenidate: A 36-Month Naturalistic Study

Abstract Aim: The objective of this study was to evaluate predictors of long-term adherence to treatment with methylphenidate (MPH). Methods: A total of 134 children (ages 4–16) with a diagnosis of attention-deficit/hyperactivity disorder (ADHD) determined by specific protocols, including a semistructured parent interview, Conners' Teacher/Parent Rating Scales, cognitive and learning evaluation, and child self-reports for anxiety and depression, were assessed monthly for up to 36 months. At the end of the study (36 months), three outcomes were evaluated (continuing medication, medication withdrawn due to functional remission, and medication withdrawn for other reasons including poor compliance). Outcomes were first analyzed by mean of the chi-squared test, Mann–Whitney-U test, or t-test, and predictive models were subsequently generated using Cox proportional hazards model analysis. Age, ADHD subtype, co-morbidity, cognitive functioning, side effects, and family and social characteristics were considered ...