[Central stimulants in adults with AD/HD. Do they help?]

This article is a review of five controlled studies of the efficacy of methylphenidate in adults with attention deficit/hyperactivity disorder (AD/HD). All five had a placebo cross-over design. In one of the studies, patients noted from the side-effects whether they were taking methylphenidate or placebo, and it is, in fact, unlikely that any of the studies were blind. The diagnostic criteria used in two of the studies were not appropriate according to present knowledge, leaving three samples of subjects meeting the present criteria for AD/HD. In one study, the patient material was extremely selective: 74% of subjects belonged to social class 1 and 2, and only 35% of those who came for treatment were eligible. Only one study has an acceptable (though not perfect) design. In this study of patients in a psychiatric clinic, no difference was found between methylphenidate and placebo. In two studies, subjects who improved on methylphenidate were followed up. Of the total of 24 subjects in these two samples, only four continued with methylphenidate after 3-12 months; two of them suffered from narcolepsy and one was a substance abuser. Thus, the efficacy of methylphenidate on AD/HD in adults has not been demonstrated. Present research is more against than in favour of its existence.