Double-blind and triple-blind assessments of medication and placebo responses in hyperactive children.

Hyperactive boys taking psychostimulant medication were studied using a randomized, placebo-controlled, crossover design. Behavior ratings and medication guesstimates were obtained for the boys when they were given methylphenidate (Ritalin) and when they were given a placebo. The ratings showed positive medication-related changes, and the guesses, done by independent judges, were significantly better than chance. The pattern of ratings for double-blind and triple-blind raters was identical. These results imply that positive psychostimulant effects are not attributable to rater sensitization or expectancy. The medication-placebo differences were highly reliable for the group comparisons and were in the predicted direction for 21 of 22 individuals, but the magnitude of the change for many individuals was not dramatic. Implications for child psychopharmacology research and differences between clinical and experimental significance are discussed.