Home-Use tDCS is Not an Effective Treatment for Major Depressive Disorder

Lucas Borrione, MD

Credit: LinkedIn

Home-use transcranial direct current stimulation (tDCS) combined with a digital psychological intervention or digital placebo is not superior to sham for the treatment of a major depressive episode, according to a new study^.1

Prior to the study, tDCS, which involves the application of low currents through electrodes placed over the scalp, was shown to be moderately effective for treating depression when applied by trained professionals, serving as another treatment option apart from pharmacotherapy, cognitive behavioral therapy, and transcranial magnetic stimulation.

“In this randomized clinical trial involving participants with major depression, we were unable to show that fully unsupervised home-use tDCS combined with either a digital psychological intervention or digital placebo was superior to sham,” investigators wrote.

Compared to transcranial magnetic stimulation, tDCS is portable, cheaper, and has few adverse events—but it has yet to be FDA-approved for any specific medical use. As a result of the reduced cost, tDCS is sold and marketed for home use., which can further reduce patient and provider-level burden.

Led by Lucas Borrione, MD, from the department and institute of psychiatry at University of São Paulo Medical School in São Paulo, Brazil, the current study sought to determine if unsupervised home-use tDCS would also be effective for treating major depressive episodes. If effective at home, then more people would be able to receive the treatment. The double-blinded, sham-controlled trial, conducted from April 2021 to October 2022, had 3 groups: home-use tDCS plus a digital psychological intervention (double active), home-use tDCS plus digital placebo (tDCS only), and sham home-use tDCS plus digital placebo (double sham).

The study took place in participants’ home, as well as a hospital in the University of São Paulo, and included participants aged 18 to 59 years old with major depression. For inclusion, participants were required to have a score greater than 16 in the Hamilton Depression Rating Scale, 17-item version, ≥ 8 years of education, and access to a smartphone and internet at home. The cohort included 210 participants, with a mean age of 38.9 years old and 85% female (n = 180), 72% White, 6% Black, 3% Asian, 16% multiple races, and 5% races not declared.

The trial’s primary outcome was change in the Hamilton Depression Rating Scale score. The secondary outcome was clinical response rates (a reduction of ≥ 50% reduction from baseline to end point).

Participants had tDCS administrated in 2-mA, 30-minute prefrontal sessions for 15 consecutive weekdays. Of note, those randomized to sham received 1-mA, 90-second sessions. Participants also had sessions 2 times a week for 3 weeks.

The digital intervention comprised of 46 sessions on behavioral therapy with 7 modules, each about 5 minutes long. This included 5 introduction sessions, 5 behavioral activation sessions, 10 healthy diet sessions, 7 sleep hygiene sessions, and 3 future planning sessions. The digital placebo was internet browsing through the same interface.

Upon analysis, mean change in the Hamilton Depression Rating Scale score from baseline was 8.2 in double active, 8.5 in tDCS only, and 7.7 in double sham. Linear mixed-effects models did not demonstrate statistically significant group differences in treatment through HDRS-17 scores.

Estimated effect sizes between groups were:

• Double active vs. TDSC only (Cohen d, 0.05; 95% CI, -0.48 to 0.58; P = .86)
• Double active vs. double sham (Cohen d, -0.25; 95% CI, -0.76 to 0.34; P = .47)
• tDCS only vs. double sham (Cohen d, -0.25; 95% CI, -0.25; 95% CI, -0.75 to 0.27); P = .35).

Additional analysis revealed only 31% (n = 20) in the double active group, 36% (n = 26) in the tDCS-only group, and 38% (n = 28) in the double sham group had a response. On the other hand, 14% (n = 9) in the double active group, 18% (n = 13) in the tDCS group, and 21% (n = 15) in the double sham group had remission.

Investigators pointed out more skin redness and heat or burning sensations in the double-active and the tDCS-only groups. Investigators also pointed out 1 suicide attempt occurred in the tDCS-only group.

Investigators called attention to multiple limitations within their trial for clinicians to consider before overinterpretation of results. Specific limitations highlighted by investigators included the study length, limited generalizability due to patient clinical characteristics, the potential for reduced response to placebo in the home setting, and the study taking place during the COVID-19 pandemic.

“In a randomized and sham-controlled clinical trial evaluating the efficacy of fully unsupervised, remotely administered, and self-applied home-use tDCS combined with either a digital psychological intervention or digital placebo, we could not show that the active interventions differed from sham in improving depressive symptoms,” investigators concluded. “These findings indicate that unsupervised home use should not currently be recommended as a tDCS modality in clinical practice.”

^References

1. ^{Borrione L, Cavendish BA, Aparicio LVM, et al. Home-Use Transcranial Direct Current Stimulation for the Treatment of a Major Depressive Episode: A Randomized Clinical Trial. JAMA Psychiatry. Published online January 3, 2024. doi:10.1001/jamapsychiatry.2023.4948}
2. ^{Woo, D. TMS Vs. tDCS: A Deep Dive into Modern Neurostimulation Techniques. Madison Avenue TMS & Psychiatry. October 16, 2023. https://www.madisonavetms.com/blog/tms-vs-tdcs-a-deep-dive-into-modern-neurostimulation-techniques/#:~:text=Because%20tDCS%20devices%20are%20simpler,than%20TMS%20for%20many%20patients. Accessed January 8, 2024.}