Methylphenidate for pervasive developmental disorders: safety and efficacy of acute single dose test and ongoing therapy: an open-pilot study.

Objective: The aim of this study was to investigate the effects of ongoing methylphenidate (MPH) on ADHD-related and autistic symptoms in Pervasive Developmental Disorders (PDD) in children who did not present any adverse effects to an initial acute dose administered at the clinic. Methods: Participants included 13 subjects (12 males, with a mean age of 7.9 years) with PDD and moderate to severe hyperactivity/impulsivity. The severity of the symptoms assessment was based on Clinical Global Impression (CGI), Childhood Autism, Child Psychiatric and Conners Parent and Teacher Rating Scales (CPRS). Scores at baseline, and after 1 and 3 months of treatment, were compared to intent-to-treat analyses. Results: One (1) hour after a single MPH dose (0.4 mg/kg), 5 subjects exhibited increased hyperactivity, stereotypes, dysphoria, or motor tics and were rated as minimally or much worse on the CGI Global Improvement Scale. They received no further treatment with MPH. Four (4) of the remaining subjects were rated as improved, and four as unchanged; they proceeded to a 12-week open trial of MPH. Two children remained unchanged: they discontinued treatment after 1 week on maximally tolerated doses. However, in group analyses, behavioral measures of hyperactivity and impulsivity improved significantly, while autism core symptom measures were unaffected. No significant adverse effects were observed in any of the 8 subjects. Conclusions: Administering a single MPH test dose may be useful in identifying children with PDD who may benefit from prolonged therapy.