Randomized, Controlled, Crossover Trial of Methylphenidate in PDD with Hyperactivity
Research Units on Pediatric Psychopharmacology Autism Network (2005). Randomized, controlled crossover trial of methylphenidate in pervasive developmental disorders with hyperactivity. Archives of General Psychology, 62, 1266-1274.
Reviewed by Kathleen Moran, MA
Why research this topic?
Many children with autism spectrum disorders (also called pervasive developmental disorder, or PDD) have problems with hyperactivity, distractibility, and impulsiveness. In children who display these problems but do not have PDD, a primary treatment is the use of stimulant medications such as methylphenidate, which is sold under names such as Ritalin, Metadate, and Concerta. However, only two small studies have tested methylphenidate for learners who have PDD accompanied by hyperactivity. This study was designed to provide a larger and more rigorous test of this medication.
What did the researcher do?
Participants were 72 children with PDD and hyperactive or impulsive behaviors, aged 5 to 14. All participants started with a 1-week trial period to check whether they tolerated methylphenidate. For each of the next four weeks, they received a different dose of the drug: none, low, medium, or high. The order of these doses was random and differed across participants. Investigators, clinicians, participants, and families did not know what dose the participants were receiving because the pills looked the same every week. At the end of the four weeks, participants continued for another 8 weeks on the dose that had worked best for them. Participants’ hyperactive and impulsive behaviors were measured with checklists completed by teachers and parents, as well as clinician ratings.
What did the researchers find?
Thirty-five of the 72 participants (49%) were classified as methylphenidate responders, meaning that their hyperactive and impulsive behaviors decreased, according to their teachers, parents, and clinicians. However, the other participants were classified as non-responders, and 13 of 72 subjects (18%) stopped taking the medication before the end of the study because of negative side-effects. Lethargy and social withdrawal were common problems at the high dose. The investigators tested whether four characteristics of participants (IQ, age, diagnosis, and weight) predicted who would be a responder. They did not, however, find reliable associations.
What are the strengths and limitations of the study? What do the results mean?
Overall, the study showed that methylphenidate was effective in improving inattention, distractibility, hyperactivity, and impulsivity for some children with PDD. However, the medication appeared to be less effective and more likely to have side-effects than it is for children who display these behaviors but do not have PDD. The authors suggest that methylphenidate may be a reasonable choice to target hyperactivity in PDD but caution that this medication is only sometimes effective and can produce unacceptable side-effects.