Changes in energy during treatment of depression: an analysis of duloxetine in double-blind placebo-controlled trials.

AIMS The aim of this study was to assess how quickly and effectively duloxetine improves energy compared with placebo in patients with major depressive disorder (MDD). METHODS Data from 10 randomised, double-blind, placebo-controlled clinical trials examining duloxetine (40-60 mg/day) vs. placebo in patients diagnosed with MDD were analysed. Change from baseline at Week 1 through Week 8 in Hamilton Depression Rating Scale (HAM-D) retardation subscale score (Item 1 - depressed mood, Item 7 - work and activities, Item 8 - retardation and Item 14 - genital symptoms) was assessed with mixed model repeated measures analysis. Positive predictive values and negative predictive values were calculated for predictor analysis. RESULTS Patients treated with duloxetine (N = 1522) experienced statistically significantly (p ≤ 0.05) greater reductions in HAM-D retardation subscale scores vs. placebo (N = 1180) starting at Week 1 throughout Week 8 of treatment. Of the patients with early energy improvement (≥ 20% reduction in HAM-D retardation subscale scores) at Week 1, 48% achieved remission (HAM-D total score ≤ 7) at Week 8; 48% and 46% of patients who experienced early energy improvement at Weeks 2 and 4, respectively, achieved remission at Week 8. DISCUSSION We demonstrated that treatment with duloxetine, quickly and with increasing magnitude over treatment time, improves low energy symptoms. As early as 1 week after starting treatment with duloxetine, improvement of low energy may serve as a predictor of remission at end-point. CONCLUSIONS Treatment with duloxetine improves energy in patients with MDD and early response in retardation may serve as a modest predictor of remission at end-point. CLINICAL TRIALS REGISTRATION ClinicalTrials.gov. Study Identifiers: NCT00036335; NCT00073411; NCT00406848 and NCT00536471. Studies HMAQa, HMAQb, HMATa, HMATb, HMBHa and HMBHb predate the registration requirement. DATA POSTING ClinicalTrials.gov. Study Identifiers: NCT00406848; NCT00536471.