The effects of methylphenidate on learning in children with ADDH: the stimulus equivalence paradigm

Investigated the effect of methylphenidate (MPH) on the ability of children with Attention Deficit Disorder with Hyperactivity (ADDH) to learn both trained and untrained complex visual relationships and compared these findings to their school performance under identical dosage parameters. 26 children between the ages of 6 and 12 years with ADDH participated in a double-blind, placebo control, within-subjects design in which each child received four doses of MPH (5, 10, 15, 20 mg) and a placebo in a counterbalanced sequence. MPH enhanced children's learning of both taught and untaught visual relationships, and most changes were similar to, albeit less dramatic than, those obtained for the children's attention and academic performance in school. Results of group and single-subject analyses are presented and discussed with relevance to psychopharmacological research and understanding the complex relationship between learning and psychostimulants used in treating children with ADDH.