Attention-deficit/hyperactivity disorder in the context of autism spectrum disorders

Autism spectrum disorders (ASD) are frequently marked by symptoms consistent with attention-deficit/hyperactivity disorder (ADHD), namely inattention, hyperactivity, and impulsivity. Recent work has established that about half of the ASD population also meets diagnostic criteria for ADHD, although the comorbid diagnoses are precluded by the DSM-IV-TR. Individuals with co-occurring ASD and ADHD symptoms are more severely impaired, with significant deficits seen in social processing, adaptive functioning, and executive control. Children with ASD and ADHD symptoms are also prone to motor problems, which lead to especially poor outcomes. Recent work has also demonstrated high rates of ASD symptoms in a subset of children with ADHD. Medication studies have demonstrated the efficacy of methylphenidate, atomoxetine, and guanfacine, among others, in treating ADHD symptoms co-occurring with ASD. However, these effects were not as great as those seen when treating primary ADHD, and they are less well-tolerated in the ASD population.