Level 2: Mid-level evidence
Methylphenidate (Ritalin, Concerta, Daytrana, others) appears to have little or no effect in preschool children with attention-deficit hyperactivity disorder (ADHD), based on a randomized trial with a high dropout rate and small differences (J Am Acad Child Adolesc Psychiatry. 2006;45:1284-1293). The study enrolled 303 stimulant-naïve children aged 3-5.5 years with a diagnosis of ADHD and predominant hyperactive features (according to Diagnostic and Statistical Manual of Mental Disorders, 4th edition, criteria). Each child was participating in a preschool or day-care program with at least eight same-age peers for at least two half days per week. A total of 279 children were enrolled in 10 weeks of parent training, which was not well-defined; 261 children completed parent training. The open-label safety lead-in phase consisted of daily dose increases of methylphenidate from 1.25 mg twice daily to 7.5 mg three times daily over one week; 183 children continued and 169 completed the safety lead-in phase. The next phase included 165 children who were randomized to a five-week crossover titration phase with one week each of placebo, then thrice-daily 1.25 mg, 2.5 mg, 5 mg, and 7.5 mg to determine the best dose. The dose-titration phase was completed by 147 children (89%), of whom 4% had no response, 8% responded to placebo, and 88% responded to one of the methylphenidate doses.
An additional four-week randomized trial comparing the best dose vs. placebo was continued by 114 children and completed by 77 children (67.5%). Although the study was published as a positive finding, only 22% of the children had an excellent response to methylphenidate (compared with 13% of the placebo group), and this was not statistically significant.