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.