The persistence of stimulant effects in chronically treated children: further evidence of an inverse relationship between drug effects and placebo levels of response

Seventeen hyperactive children who had been treated for 1-5 years with methylphenidate were studied in a double-blind placebo-controlled crossover study. Specific measures of stimulant response were found to be inversely related to the subject's level of response in the placebo condition. This inverse relationship was previously found to characterize the clinical effects of hyperactive children in an acute-treatment paradigm. It is equally valid in a chronic-treatment study. "State-contingency" is not, therefore, simply a function of the "novelty" of initial drug treatment.