Transcranial direct current stimulation (tDCS) fails to treat depression

A new study a The Lancet found that transcranial direct current stimulation (tDCS) was no better than a placebo (dummy treatment) for depression. As a multi-center, sham-controlled, triple-blind study, this was a well-designed study with results that should be considered robust.

The research was conducted by a large team of German researchers led by Gerrit Burkhardt at the Ludwig-Maximilians-Universitt Mnchen, Munich, Germany.

According to the researchers:

Active tDCS was not superior to sham stimulation during a 6-week period. Our study does not support the efficacy of tDCS as an adjunctive treatment to SSRIs in adults with MDD.

tDCS is one of several controversial brain stimulation or neuromodulation devices, which also include transcranial magnetic stimulation (TMS). TMS involves using a large machine to deliver electrical impulses to the brain, while tDCS is a small device that delivers a low, constant electrical current to the brain.

While TMS is approved by the FDA for the treatment of depression and OCD, tDCS has not received FDA approval for any indication. tDCS devices are sometimes purchased online and used at home by people who identify themselves as biohackers, although websites typically include a warning that users should not use them themselves for medical purposes.

The study included 150 people with, on average, moderate depression. All of the participants had treatment-resistant depression, which means that at least one SSRI had failed to improve their depression in this study. In the study, they continued on the ineffective drug throughout treatment.

The intent of the study was to see whether tDCS, in addition to ineffective SSRI treatment, would lead to improvement in depression rating scales.

Only about 7% of the participants had tried psychotherapy.

In the study, 77 participants received tDCS, while 73 participants received a dummy treatment, a fake version of tDCS designed to look like the real thing. Participants received treatment sessions every day for four weeks and then two additional sessions per week for another two weeks (six weeks of treatment total).

The study was triple-blind, meaning that none of the subjects involved knew whether the participants were receiving real or sham tDCS. It was also conducted in eight different hospitals in Germany, which helps lend real-world validity to the findings (since we know they are not guided by the experience of a single centre).

There was no difference in improvement on any of the outcomes between the two groups at six weeks, including the primary outcome of the MADRS Depression Scale and the secondary outcomes of BDI-II, CGI-S, GAF, SF-36, SHAPS -D, and STAI scores. This remained true at both the 18-week and 30-week follow-ups.

In terms of remission (no longer suffering from depression), more people in the placebo group improved within six weeks: 38% versus 31% (this difference was not statistically significant). That is, approximately one-third of those with moderate treatment-resistant depression are no longer depressed within six weeks, whether or not they receive treatment and this despite being continued on a treatment (SSRI) that was already rated as ineffective for them before starting. I study.

Although tDCS was ineffective in treating depression, it did do some harm, including an increase in self-harm behavior.

The active group had a higher incidence of headaches, sleep-related problems, local reactions at the treatment site (eg, burning sensation or skin irritation), restlessness, nausea, flash visions, and self-harm behavior, they write. researchers.

Sixty percent of those who received tDCS experienced adverse effects, while 43% of those in the sham group reported adverse effects.

Despite their null finding, the researchers write:

Future research should focus on advancing the neurobiological understanding of the effects of tDCS on depressive symptoms and incorporating technological developments to establish individualized tDCS as an alternative to the so-called one-size-fits-all approach.

This statement, a call for research into the purported effects of tDCS on depressive symptoms and a call for establishing individualized tDCS, despite finding that the treatment was no better than placebo, may be explained by the long-standing financial conflicts of interest held by many of the researchers involved. Some have been funded by companies in the brain stimulation industry, including Neuromod and Brainsway, as well as many other pharmaceutical and device companies. Some of these companies have been supplied with unspecified brain stimulation equipment, which can cost hundreds of thousands of dollars (although tDCS devices in particular are relatively inexpensive). At least one researcher in the study has a patent pending for brain stimulation devices and is chairman of the executive board of the German Society for Brain Stimulation in Psychiatry.

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Burkhardt, G., Kumpf, U., Crispin, A., Goerigk, S., Andre, E., Plewnia, C., . . . & Padberg, F. (2023). Transcranial direct current stimulation as adjunctive treatment to selective serotonin reuptake inhibitors in adults with major depressive disorder in Germany (DepressionDC): a triple-blind, randomized, sham-controlled, multicenter study. Hand. Published online July 3, 2023. https://doi.org/10.1016/S0140-6736(23)00640-2 (Link)