Pharmacotherapy of Attention Deficit Hyperactivity Disorder Symptom Profile in ASD
Simonoff et al. (2008) has reported 25% to 30% prevalence of attention deficit hyperactivity disorder (ADHD) in autism spectrum disorder (ASD). Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, now allows for both diagnoses to make concurrently. Here, I would try to summarize the available literature on pharmacotherapy addressing ADHD symptom profile in ASD whilst examining extant evidence.
A systematic review and meta-analysis of four randomized controlled trials (RCTs) by Reichow et al. (2013) reveal an effect size of 0.67 for methylphenidate (MPH) to address ADHD in ASD. Generally speaking, efficacy observed is less than in typically developing children with ADHD only; side effects tend to be more with up to 18% drop-outs, and medium-range doses are used.
Beyond actions on ADHD, Jahromi et al. (2009) examined the effect of MPH on social communication and self-regulation skills in 33 children with ASD. MPH use was associated with improved initiation for joint attention, improved response to bids for joint attention, better self-regulation, and more regulated affective state.
The nonstimulant atomoxetine (ATX) was effective in two RCTs: one cross-over design study by Arnold et al. (2006) showing large effect on hyperactivity subscale of aberrant behavior checklist (ABC) and reasonable tolerability; the other is a parallel design by Harfterkamp et al. (2014), where ATX ameliorated hyperactivity, stereotypy, and inappropriate speech subscales on ABC.
α2 agonists were historically preferred in the ASD population but with only flimsy evidence base. Two small RCTs—one (11 cases) by Handen et al. (2008), using guanfacine and reporting utility on hyperactivity subscale of ABC but with several side effects; the other (8 cases) by Jaselskis et al. (1992), reporting modest efficacy of clonidine on irritability subscale.
Finally, the Food and Drug Administration approved both risperidone and aripiprazole for behavioral facets in ASD, which might be extrapolated to ADHD symptom profile, with an effect size of 0.6 to 1.
Needless to say, pharmacotherapy should always be coupled with behavioral and educational interventions. Close monitoring of side effects is strongly warranted in this vulnerable population.