Five-Fold Increase in National Prevalence Rates of Attention-Deficit/Hyperactivity Disorder Medications for Children and Adolescents with Autism Spectrum Disorder, Attention-Deficit/Hyperactivity Disorder, and other Psychiatric Disorders: A Danish Register-Based Study

Abstract Objective: The purpose of this study was to estimate the prevalence and time trends in prescriptions of methylphenidate, dexamphetamine, and atomoxetine in children and adolescents, within three diagnostic groups: 1) autism spectrum disorder (ASD), 2) attention-deficit/hyperactivity disorder (ADHD), and 3) other psychiatric disorders. Methods: Data from six different national registers were used and merged to identify a cohort of all children and adolescents born in Denmark between 1990 and 2001 (n=852,711). Sociodemographic covariates on cohort members and their parents and lifetime prescriptions of methylphenidate, dexamphetamine, and atomoxetine were extracted from the registers. Prescriptions were also stratified by duration (