An open-label trial of OROS methylphenidate,in adults with late-onset ADHD

Introduction: Many adults with current impairing symptoms of attention-deficit/hyperactivity disorder (ADHD) do not report an age at onset before 7 years of age and cannot, therefore, be assigned the full Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnosis of ADHD. We hypothesized that treatment with oral-release osmotic system (OROS) methylphenidate (MPH) will be safe and efficacious for the treatment of adults with late-onset ADHD. Method: This was a 6-week, open-label, prospective treatment study of OROS MPH monotherapy in 36 adult patients with late-onset ADHD (onset later than the required 7 years of age) using standardized instruments for diagnosis and a robust oral daily dose of up to 1.3 mg/kg/day. Symptom severity was assessed with the Adult ADHD Investigator Symptom Report Scale (AISRS) and the Clinical Global Impression (CGI) scale. Results: Subjects reported robust current symptoms of ADHD at pre-treatment baseline (11.1 +/- 2.8 DSM-IV symptoms), but had an atypical mean age at onset of 14.2 +/- 8.6 years.Treatment with OROS MPH at an average daily dose of 78.2 +/- 29.4 mg was associated with a statistically and clinically significant reduction in ADHD symptoms relative to baseline as assessed through the AISRS (-16.4 +/- 10.5; P <.001). Using a categorical definition of response (CGI-I much or very much improved), a majority (n=26; 72%) of subjects were rated as improved at endpoint. Conclusion: These results extend previous findings in adults with full ADHD to adults meeting criteria for late-onset ADHD and support the need for further controlled clinical trials in this population.