ADHD symptom prevalence and risk factors in a sample of toddlers with ASD or who are at risk for developmental delay.

Individuals with attention deficit/hyperactivity disorder (ADHD) experience difficulties with inattention, hyperactivity, and impulsivity which significantly interfere with their daily functioning. Symptoms of the disorder occur in children, but the developmental trajectory of ADHD symptoms is not known. The present study examines the prevalence of ADHD symptomology in a sample of 2956 children who were determined to be at risk for developmental delay. Prevalence rates for ADHD in the overall sample was 4.50%, and prevalence rates by gender, race, and presence of autism spectrum disorder (ASD) were comparable. The prevalence was not significantly different in children with an ASD diagnosis. No significant effects of gender or ASD diagnosis were observed. ADHD should be considered as a diagnosis among young children who present to clinics for children at risk for developmental delay, and future researchers should further study its developmental trajectory, beginning at an early age.