Hyperkinetic/aggressive boys in treatment: predictors of clinical response to methylphenidate.

Data on 84 nonretarded boys aged 6--12 with the hyperkinetic/MBD syndrome were drawn from a comprehensive, longitudinal investigation in the interest of identifying factors that contribute significantly to variation in clinically rated improvement during treatment with methylphenidate. The size of the multiple correlation (R = .50) indicates that 25% of the variation in the children's response to methylphenidate is jointly predictable from age at referral, degree of perinatal complications, and score on the hyperactivity factor. The authors discuss stepwise multiple regression analysis as the method of choice in drug response prediction studies and the possible effects on the results of such studies of differing definitions of improvements.