Effects of Transcranial Direct-Current Stimulation Therapy on Primary Chronic Insomnia: A Proof-of Concept Clinical Trial

Objectives: To assess the effect and safety of transcranial direct-current stimulation (tDCS) in primary chronic insomnia. Methods A one-month, double-blind, randomized, sham-controlled trial was performed. A total of 7 patients with primary chronic insomnia received tDCS using anodal (n=3), cathodal (n=2), or sham stimulation (n=2). They were followed up at 1 week and 1 month after treatment. The primary outcome measures included improvement in total sleep time (TST), sleep latency (SL), and sleep efficiency (SE) at 1 month follow-up. Results TST and SE were improved with tDCS at 1 month follow-up in all patients (100%) of the anodal group, one (50%) of the cathodal group, and one (50%) of the sham group. tDCS improved SL at 1 month follow-up in two patients (67%) of the anodal group, one (50%) of the cathodal group, and none (0%) of the sham group. With respect to adverse events, transient itching sensation occurred in one patient of the anodal group. None of the other groups reported adverse events. Conclusions Our results suggest that tDCS may be effective and safe for treatment of primary chronic insomnia. A larger controlled study needs to be further investigated. Keywords: Primary chronic insomnia, Transcranial direct-current stimulation (tDCS), Non-pharmacological treatment.