As at-home, do-it-yourself (DIY) brain stimulation devices like transcranial direct current stimulation (tDCS) gain popularity for common psychiatric conditions like depression, anxiety, and posttraumatic stress disorder (PTSD), questions arise about their safety and efficacy.
However, the US Food and Drug Administration (FDA) has yet to “fully” clear any of these devices and has only granted breakthrough device designation to a few. In addition, most of the portable products don’t market themselves as medical interventions, putting them into a regulatory “gray area” that has little oversight.
This has led to a free-for-all environment, allowing individuals to purchase these products online and self-administer “treatment” — often without the guidance or even knowledge of their healthcare providers.
So how effective and safe are these noninvasive brain stimulators, and what guidance, if any, should clinicians provide to patients who are or are contemplating using them at home; what does the research show, and what are the ethical considerations?
What the Research Shows
Data from studies examining unsupervised at-home and use under medical supervision are mixed. Results from a recent randomized trial of more than 200 participants showed no significant difference in safety or efficacy between adjunctive at-home tDCS and at-home sham tDCS for depressive symptoms.
“To be fair, they did not find any unexpected safety issues. What they did find was that there was no clear signal that it worked,” said Noah S. Philip, MD, professor of psychiatry and human behavior, Warren Alpert Medical School of Brown University, Providence, Rhode Island.
Philip, who is also lead for mental health research at Brown’s Center for Neurorestoration and Neurotechnology, Providence, Rhode Island, and was not involved in the study, noted that while other research papers have shown more promising results for depression and other conditions such as adult attention-deficit/hyperactivity disorder (ADHD) and pain, they often are not placebo controlled or include large numbers of patients.
Still, he added the growing use of these devices reflects the fact that standard treatment often doesn’t meet patients’ needs.
“Broadly speaking, part of the hope with brain stimulation is that instead of taking a pill, we’re trying to more directly affect the brain tissues involved — and therefore, avoid the issue of having systemic side effects that you get from the meds. There’s certainly a hunger” for better interventions, Philip said.
tDCS involves a low-intensity electrical current applied through electrodes on the scalp in order to influence brain activity. Generally speaking, it emits less energy than other types of noninvasive brain stimulation, such as transcranial magnetic stimulation. “The trade-off is that’s it also a little harder to find a clear signal about how it works,” Philip said.
As such, he added, it’s important for clinicians to familiarize themselves with these devices, to ask about patient use, and to set up structured assessments of efficacy and adverse events.
Results from a randomized trial published last year in The Lancet showed no significant benefit for in-office use of tDCS plus a selective serotonin reuptake inhibitor vs sham tDCS for major depression.
On the other hand, a randomized trial published earlier this year in Brain Stimulation showed that older adults who received active tDCS had greater reductions in depressive and anxiety symptoms than those in the sham group.
In addition, results from a small study of eight participants published last year in SAGE Open Medicine showed adjuvant tDCS helped patients with refractory PTSD. Finally, a randomized trial of 54 veterans from Philip’s own team showed tDCS plus virtual reality was effective for combat-related PTSD.
Although there have also been several studies showing possible benefit of tDCS for Alzheimer’s disease, Gayatri Devi, MD, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, noted in a Medscape Neurology Decision Point that “the problem with all these studies is that they’re all very small, and there [are] so many different variables in terms of how you interpret response.”