Pharmacotherapy of Attention-Deficit/Hyperactivity Disorder in Individuals with Autism Spectrum Disorder.

Attention-deficit/hyperactivity disorder (ADHD) is the most frequent comorbid disorder that is observed at a higher rate and with greater morbidity in higher intellectually functioning populations with autism. Up to 85% of the populations with autism and 15% of individuals with ADHD suffer from a reciprocal comorbidity that is highly under-recognized in intellectually capable populations. Limited empirical evidence is available on the response of anti-ADHD agents in autism populations with ADHD. In autism spectrum disorder (ASD) populations, response to methylphenidate for the treatment of hyperactivity is worse than typically expected in the presence of the intellectual disability. The anti-ADHD response to atomoxetine in autism populations is worse than typically expected although tolerability is similar to that observed in the typicals. The hyperactivity response to guanfacine treatment in predominantly intellectually impaired populations with ASD is as robust as observed in the typicals although tolerability was worse than typically expected. Further trials are warranted to document the extent of atypical anti-ADHD response in intellectually capable populations with autism.