A randomized, double-blind clinical trial on the efficacy of cortical direct current stimulation for the treatment of major depression

Abstract

Preliminary findings suggest that transcranial direct current stimulation (tDCS) can have antidepressant effects. We sought to test this further in a parallel-group, double-blind clinical trial with 40 patients with major depression, medication-free randomized into three groups of treatment: anodal tDCS of the left dorsolateral prefrontal cortex (active group - 'DLPFC'); anodal tDCS of the occipital cortex (active control group - 'occipital') and sham tDCS (placebo control group - 'sham'). tDCS was applied for 10 sessions during a 2-wk period. Mood was evaluated by a blinded rater using the Hamilton Depression Rating Scale (HDRS) and Beck Depression Inventory (BDI). The treatment was well tolerated with minimal side-effects that were distributed equally across all treatment groups. We found significantly larger reductions in depression scores after DLPFC tDCS [HDRS reduction of 40.4% (+/-25.8%)] compared to occipital [HDRS reduction of 21.3% (+/-12.9%)] and sham tDCS [HDRS reduction of 10.4% (+/-36.6%)]. The beneficial effects of tDCS in the DLPFC group persisted for 1 month after the end of treatment. Our findings support further investigation on the effects of this novel potential therapeutic approach - tDCS - for the treatment of major depression.

Figure 1

Plots showing mood scores changes [as indexed by the Hamilton Depression Rating Scale (HDRS)] over time (t₀, baseline; t₁, immediately after treatment; t₂, 15 d after end of treatment; t₃, 30 d after the end of treatment). Each data-point represents HDRS mean score; error bars indicate s.e.m. –■–, DLPFC tDCS; ····▲····, occipital tDCS; - -●- -, sham tDCS.

Figure 2

Depression scores changes immediately after 10 d of stimulation compared with baseline in the three groups of treatment. Each column represents mean Hamilton Depression Rating Scale (HDRS) score reduction; error bars indicate s.e.m.