Osmotic-Release Oral System Methylphenidate Augmentation of Antidepressant Monotherapy in Major Depressive Disorder: Results of a Double-Blind, Randomized, Placebo-Controlled Trial

Objective: To evaluate the efficacy, safety, and tolerability of adjunctive osmotic-release oral system (OROS) methylphenidate in outpatients with major depressive disorder (MDD) receiving a stable oral antidepressant regimen.

Method: This multicenter, double-blind, randomized, placebo-controlled, parallel-group, 5-week trial enrolled 145 subjects who met DSM-IV-TR criteria for MDD and who had failed 1 to 3 previous antidepressant monotherapies (including current antidepressant) of adequate dose and duration. Augmentation therapy was initiated with 18 mg of OROS methylphenidate and increased to a maximum dose of 54 mg of OROS methylphenidate until an optimal dose was achieved. Efficacy scales included the Montgomery-Asberg Depression Rating Scale (MADRS), 7 atypical items from the 31-item Hamilton Rating Scale for Depression, the Clinical Global Impressions-Severity of Illness (CGI-S) scale, the CGI-Improvement scale (CGI-I), the Sex Effects scale, the Multidimensional Assessment of Fatigue (MAF) scale, and the Apathy Evaluation Scale (AES). Subjects were recruited at 17 community and academic centers across Canada. The study was conducted from June 8, 2005, to April 18, 2006.

Results: There was no statistically significant difference between the groups at endpoint on the MADRS. OROS methylphenidate was superior to placebo in improving apathy and fatigue as measured by the AES and the MAF. Statistically significant differences using mixed-model analysis were observed on the AES at all visits and at endpoint (p = .01) and on the MAF (p < .01). No differences were observed on other secondary measures, including the CGI-I and CGI-S. There were no clinically significant findings on electrocardiogram.

Conclusions: OROS methylphenidate did not demonstrate statistical significance on the MADRS at endpoint. Apathy and fatigue were significantly improved with OROS methylphenidate treatment, which was well tolerated with minimal side effects.