Multiscale assessment of treatment efficacy in adults with ADHD: A randomized placebo-controlled, multi-centre study with extended-release methylphenidate

OBJECTIVES This trial was performed to test the efficacy and safety of an extended-release formulation of methylphenidate (MPH ER). METHODS A total of 162 adults with ADHD according to DSM-IV were treated for 8 weeks with either two daily individually body weight-adjusted doses of MPH ER up to 1 mg/kg per day (N = 84) or placebo (N = 78). The primary efficacy outcome was the Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS) 8 weeks after randomization. Secondary efficacy measures were the ADHD Diagnostic Checklist (ADHD-DC), the Conners Adult Attention Deficit Disorder Scale (CAARS-S:L), the Clinical Global Impression (CGI) and the Sheehan Disability Scale (SDS). RESULTS At week 8 a significantly higher decline of the total WRAADDS score was found in the MPH ER group as compared to the placebo group (P = 0.0003). The rates of responders were 50% in the MPH ER and 18% in the placebo group (P < 0.0001). Furthermore, similar effects were observed for the secondary efficacy variable: ADHD-DC score (P = 0.004), CAARS-S:L score (P = 0.008) and the SDS score (P = 0.017). 50% of the MPH ER group and 24.4% of the placebo group were improved "much" or "very much" according to the CGI rating (P = 0.0001). MPH ER treatment was well tolerated. At week 2 also the mean heart rate was significantly higher in the MPH ER group as compared to the placebo group (P = 0.01). No differences between the study groups were observed regarding mean blood pressure at any visit. CONCLUSIONS This clinical trial demonstrated statistically significant and clinical relevant effects of MPH ER in adults with ADHD for several self- and investigator-rated ADHD psychopathology and also functional efficacy measures.