Home-based transcranial direct current stimulation for major depressive disorder: 6-month follow-up from randomised sham-controlled trial and open-label treatment phases

Transcranial direct current stimulation (tDCS) is a potential home-based treatment for major depressive disorder (MDD). In our double-blind randomised controlled trial (RCT) (n = 174; UK and USA), a 10-week course of home-based tDCS demonstrated clinical efficacy (clinical response: 58.3 % active treatment arm and 37.8 % sham (p = 0.017). tDCS was delivered in a bifrontal montage, with anode over left dorsolateral prefrontal cortex (DLPFC) and cathode over right DLPFC. Each session was 30 min, with active stimulation at 2 mA and sham at 0 mA, incorporating brief ramp-up and ramp-down phased. Following the 10-week RCT, all participants were offered active tDCS in a 10-week open-label treatment phase, with 111 participants completing this phase. UK cohort (n = 77 MDD) were invited for additional 3-month and 6-month follow-ups, extending the total study period to 11 months post-randomisation. Participants were able to continue using the tDCS device during follow-up. At least one follow-up visit was attended by 42 MDD participants (27 women). Device usage rates were 59 % at 3-month follow-up and 55 % at 6-month follow-up. Clinical response rate was 64 % at 3-month follow-up and 76 % at 6-month follow-up. Among participants who had shown a clinical response after the open-label phase, 90 % maintained their response at the 6-month follow-up. In summary, long-term follow-up showed high and sustained clinical response rates regardless of continued tDCS device use.