In a more rigorous study of 66 children with PDD and hyperactivity conducted by Dr. Scahill and his colleagues, methylphenidate improved hyperactivity significantly but to a lesser degree than it would in typically developing children with ADHD, according to teacher and parent ratings (Arch. Gen. Psychiatry 2005;62:1266–74). Children in the randomized, double-blind, crossover trial tolerated three dose levels of methylphenidate during a 7-day test dose period and then received placebo for 1 week, followed by 3 weeks of the three methylphenidate doses in random order.
Thirty-four patients who responded to treatment based on a less conservative definition of response later received 8 weeks of open-label methylphenidate at an individually determined best dose. Adverse events such as decreased appetite and increased repetitive behavior and stereotypies occurred mainly with the highest dose, even though it was “not really that high” (0.5–0.6 mg/kg per dose), Dr. Scahill said. Few adverse events occurred in the 38% (25 of 66) of patients who responded to either the low (0.125–0.18 mg/kg per dose) or the medium dose (0.25–0.35 mg/kg per dose).
Liquid fluoxetine proved to be more effective in treating repetitive behaviors than placebo. DR. SCAHILL