Stimulant Treatment Is Associated with Improvements In ADHD Symptoms—and Not with Increased Irritability or Social Problems—In Children with ASD with Significant ADHD Symptomatology

Background:  Although psychostimulant treatment of ADHD symptoms in children with ASD has been shown to reduce symptoms of hyperactivity, and to some extent improve cognition, it has also been associated with undesirable increases in irritability and social withdrawal.  To date, little is known regarding the behavioral effects of extended release stimulant medication, the current standard of treatment, in children with ASD and significant ADHD symptomatology.  

Objectives:  The primary objectives of this study were to to examine the effectiveness of extended release methylphenidate (MPH) on behavioral functioning in children with ASD and significant symptoms of ADHD, and to determine if higher doses of  MPH were associated with progressive behavioral improvement—or if initial improvement was followed by lesser improvements (or even behavioral declines) at higher doses.

Methods:  The behavioral effects of four doses of MPH were investigated using a within-subject, crossover, placebo-controlled design in 24 children (mean: CA=8.6 yrs, FSIQ=84) who met DSM-IV-TR criteria for ASD on the ADI-R and on the ADOS.  Dosing strategy was based on the experience from the MTA Study, as well as the RUPP MPH trial.  Parent and teacher behavioral ratings were obtained at each MPH dose.

Results:  Both parents and teachers noted significant declines in symptoms of hyperactivity and impulsivity with MPH treatment. Although parents reported significant improvements in attention and social skills, teachers saw less evidence of improvement in these areas. Higher doses of MPH were associated with successive improvements in behavior.  Interestingly, there was no increase in irritable behavior at higher MPH doses—in fact, there was a significant decline in irritability across the MPH dose range examined in this study.  There was also no evidence of decline in social function with increasing MPH doses.

Conclusions:  Our findings suggest that stimulant treatment using extended release MPH in children with ASD and significant symptoms of ADHD is associated with significant improvement in ADHD symptomatology, particularly with regard to hyperactivity and impulsivity.  Interestingly, a comparison of parent and teacher ratings suggest that the effects of MPH treatment on attention and social skills may be somewhat less consistent between the home and school settings.  These findings suggest that both parent and teachers provide crucial pieces of information when titrating MPH treatment in children with ASD who have significant ADHD symptomatology.