BACKGROUND:

There are few controlled studies of methylphenidate hydrochloride in adults with attention-deficit hyperactivity disorder (ADHD), and their results have been equivocal. The discrepancies among these studies may be related to low doses, diagnostic uncertainties, and lack of attention to comorbid disorders.

METHODS:

We conducted a randomized, 7-week, placebo-controlled, crossover study of methylphenidate in 23 adult patients with DSM-III-R ADHD using standardized instruments for diagnosis, separate assessments of ADHD and depressive and anxiety symptoms, and a robust daily dose of methylphenidate hydrochloride, 1.0 mg/kg per day.

RESULTS:

We found a marked therapeutic response for methylphenidate treatment of ADHD symptoms that exceeded the placebo response (78% vs 4%, P < .0001). Response to methylphenidate was independent of gender, psychiatric comorbidity with anxiety or moderate depression, or family history of psychiatric disorders.

CONCLUSION:

Robust doses of methylphenidate are effective in the treatment of adult ADHD.