tDCS treatment significantly improves depressive symptoms and boosts clinical response and remission rates, with no serious device-related adverse events reported.
Study: Home-based transcranial direct current stimulation treatment for major depressive disorder: a fully remote phase 2 randomized sham-controlled trial. Image Credit: Elif Bayraktar/Shutterstock.com
In a recent study published in Nature Medicine, researchers evaluated the efficacy, acceptability, and safety of a fully remote, home-based transcranial direct current stimulation (tDCS) treatment for major depressive disorder (MDD) in a 10-week randomized, sham-controlled trial.
Background
MDD is a prevalent condition that often leads to disability and suicide. It is characterized by prolonged low mood and disturbances in sleep, appetite, energy, and cognitive function. While antidepressants and psychotherapy are common treatments, many patients do not fully recover. tDCS, a non-invasive brain stimulation method, has shown potential in improving neural networks linked to MDD. However, further research is needed to verify its long-term effectiveness, refine treatment protocols, and better understand its mechanisms in home-based applications for MDD.
About the study
The study was a multisite, double-blind, placebo-controlled, randomized superiority trial evaluating 10-week home-based tDCS treatment for MDD, followed by a 10-week open-label treatment. Participants were selected from the United Kingdom (UK) and the United States of America (USA) and provided informed consent. The relevant research ethics committees granted ethical approval.
Participants were adults diagnosed with MDD, with moderate or greater depressive symptom severity, determined through structured clinical interviews. The trial excluded individuals with treatment-resistant depression, high suicide risk, or comorbid psychiatric disorders.
Participants were randomly assigned to receive either sham or active tDCS treatment. The active tDCS group received 2 mA direct current stimulation for 30 minutes per session, with a ramp-up and ramp-down to mimic active stimulation for the sham group. The treatment protocol included five tDCS sessions per week for three weeks, followed by three sessions per week for seven weeks. Randomization and treatment assignments were independently conducted in the UK and the USA.
Real-time remote monitoring allowed researchers to supervise participant adherence. Blinding procedures ensured that both participants and researchers were unaware of treatment allocation. Depressive symptom severity was measured using standardized clinical scales at various time points, with the primary outcome being the difference in symptom severity between the active and sham treatment groups at week 10.
Study results
Between May 12, 2022, and March 10, 2023, the study recruited 2,234 individuals through initial telephone screening. A total of 368 participants provided written informed consent and completed a Microsoft Teams videoconference assessment. Of these, 174 individuals with MDD, 120 of whom were women (69%), were enrolled. The mean age of participants was 37.63 years (SD = 11.00), and most participants (83.3%) identified as white.
All participants met the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for MDD and were in a current depressive episode with a Hamilton Depression Rating Scale (HDRS) score of 16 or greater (mean HDRS = 19.07, SD = 2.73). The median number of depressive episodes was three.
Participants were required to be either treatment-free or on stable antidepressant medication or psychotherapy for at least six weeks prior to enrollment. The cohort composition included 32.8% who were treatment-free, 62.6% on antidepressant medication, 14.9% in psychotherapy, and 10.3% in both medication and psychotherapy. Randomization allocated 87 participants to active tDCS treatment and 87 to sham tDCS. After excluding one participant who did not begin treatment, the modified intention-to-treat sample included 173 participants.
The primary outcome of the study was a significant reduction in depressive symptoms, with participants in the active tDCS group showing a 9.41 point reduction in HDRS scores (SD = 6.25), compared to a 7.14 point reduction in the sham group (SD = 6.10). The estimated week 10 mean HDRS score for the active group was 9.58 (SD = 6.02) versus 11.66 (SD = 5.96) in the sham group (95% confidence interval = 0.51-4.01, P = 0.012).
Secondary outcomes showed that the active tDCS group had significantly higher clinical response rates (58.3% vs. 37.8%) and remission rates (44.9% vs. 21.8%) compared to the sham group. Similar improvements were seen in Montgomery–Åsberg Depression Rating Scale (MADRS) scores, with the active group achieving a greater reduction in depressive symptoms and higher rates of clinical response and remission.
The study observed no significant differences in quality of life measures between the groups. Adverse events, including skin redness, irritation, and trouble concentrating, were more common in the active tDCS group, but there were no serious adverse events or instances of mania or hypomania.
Conclusions
To summarize, in this international, multisite, sham-controlled randomized controlled trial (RCT) of home-based tDCS for MDD, a 10-week course of active tDCS significantly improved depressive symptoms, clinical response, and remission rates compared to sham stimulation.
Clinician-rated (HDRS and MADRS) and self-reported (MADRS-s) assessments demonstrated these benefits. The active treatment arm showed response and remission rates 2-3 times higher than the sham group.
The trial demonstrated efficacy across a range of MDD presentations, including first-episode, recurrent, and treatment-resistant depression, suggesting that home-based tDCS may be an effective treatment option for MDD.
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