Methylphenidate effects on symptoms of attention deficit disorder in adults

The objectives of this study were (1) to determine whether attention deficit disorder (ADD) is a specific diagnostic entity in adulthood; (2) to evaluate, using a double-blind crossover design, the efficacy of methylphenidate hydrochloride in adults with evidence of residual ADD with hyperactivity (ADD-H) (N = 26); and (3) to evaluate the specificity of drug response by also administering methylphenidate to patients with similar adult symptoms but no childhood history of ADD-H (N = 35). Results indicated success in differentiating relatively distinct groups. However, no overall benefit from methylphenidate was evident, regardless of childhood history of ADD-H. Approximately 25% of the sample appeared clinically to benefit from methylphenidate, but no clear-cut predictors of drug response were identified; history of drug abuse (polydrug) appeared to be the best predictor. Even among the responders, benefit was generally not as marked nor as clinically valuable as in childhood ADD-H.