Methylphenidate in severely retarded residents and the clinical significance of stereotypic behavior.

Abstract

An attempt was made to evaluate a model predicting stimulant drug response based on attentional characteristics of the participants. Twenty-eight severely and profoundly mentally retarded residents took part in a double blind, placebo controlled trial of methylphenidate (Ritalin). Methylphenidate was administered, for one week each, in a low dose of 0.3 mg/kg and a high dose of 0.6 mg/kg. The results failed to show any clinically relevant differences between placebo and active drug conditions with the exception that methylphenidate caused a significant reduction in food consumption. A variety of subject characteristics, including level of stereotypy, hyperactivity, and IQ were unrelated to drug effect. One positive finding, unrelated to drug effects, was that subdivision of the group by degree of stereotypy provided substantial clinical information about individual subjects.