Examining the Validity of ADHD as a Diagnosis for Adolescents with Intellectual Disabilities: Clinical Presentation

Children with intellectual and developmental disabilities are at heightened risk for mental disorders. Using current diagnostic criteria, disruptive behavior disorders, specifically Attention-Deficit/Hyperactivity Disorder (ADHD), appear to be the most prevalent co-occurring disorders. However, the validity of ADHD as a diagnosis for children and adolescents with intellectual disabilities remains unclear. The present study examined the clinical presentation of ADHD (prevalence, sex differences, and comorbidity) among adolescents with and without intellectual disability (ID) as well as investigated the validity of ADHD for adolescents with ID by examining similarities in terms of symptom presentation, developmental course, and associated functional impairment. The sample included 142 adolescents and their families, about a third of whom were classified in the ID group and the remaining were in the typically developing (TD) group. Findings indicated that adolescents with ID continue to be at elevated risk for ADHD (risk ratio: 3.38:1) compared to their typically developing peers. Additionally, the presentation of ADHD appeared similar among adolescents with and without ID, supporting the validity of an ADHD diagnosis for this population of adolescents. Implications for public policy and intervention are discussed.