The last 15 years have seen a resurgence of interest among medical researchers in transcranial direct current stimulation, or tDCS. It’s a mild form of brain stimulation that uses a direct, constant, low current delivered to the brain via electrodes—typically placed at both sides of the forehead to stimulate the prefrontal cortex. Some studies suggest this stimulation can help alleviate depression, offering a potential alternative for patients who want to avoid medication and the more severe electroconvulsive therapy.
Studies have also suggested the treatment could enhance cognition, which inevitably led to a do-it-yourself tDCS community forming online. So while research into the medical uses for tDCS has crept slowly forward, alongside it runs a parallel track of lay experimenters using themselves as guinea pigs. And a market has evolved for homebrew tDCS kits, too; many promise the kinds of cognitive improvements that science can’t yet prove. The growing number of experimenters—and businesses willing to cater to them—has some scientists and researchers concerned.
“I highly discourage the do-it-yourself tDCS,” says Veronica Galvez. She’s a visiting psychiatrist and clinical research officer with the Black Dog Institute—a Sydney, Australia-based research and treatment clinic. The institute specializes in mood disorders, including depression and anxiety; it’s currently conducting a tDCS trial. Galvez points out that such trials require a long screening process designed to keep participants safe; they’re conducted by teams of psychiatrists, neuropsychologists, and experienced post-doctoral researchers. “It’s not only that you need specific training; it’s that you need to know your medical and psychiatric conditions,” she says. Technique is important and must be standardized; you’re running electrical current into the brain, after all. “The people commercializing these devices,” she says, “are not taking these issues into account.”
Her colleagues have already had some success. In 2012, an Institute trial found that in its 64 patients with depression, trial treatment produced a “significantly greater improvement in mood after active than after sham treatment,” over a three-week period. And, Galvez says, the treatment is relatively painless: Patients stay alert and awake; they may feel itching or tingling around the electrodes, and there’s been the occasional headache.
Galvez says that’s appealing to trial participants. Some have found the side effects of antidepressants intolerable; some have failed to respond to the drugs, or have stopped responding to them. That leaves tDCS as an option before trying electroconvulsive therapy (ECT), which involves full anesthesia and electrically induced seizures.
Those advantages appeal to the DIY users as well. On Reddit’s tDCS community, many anonymous users describe using the technique to treat mental disorders, including depression and anxiety. Alexander Mark is one of them. A 63-year-old Michigan resident, he says, “I am afflicted with Bipolar Disorder II, and learned about tDCS in an effort to find a way to relieve myself of the severe depression that often comes with the illness.” He began trying it when his medication proved ineffective (though that’s no longer the case), and he’s only had a single negative experience—when he misplaced an electrode. (He currently uses the Chattanooga Ionto iontophoresis system, which sells for about $700 through third-party merchants on Amazon.)
Others use tDCS purely for enhancement—or the subjective feeling of enhancement. Peter Simpson-Young, a graduate student in health technology innovation at the University of Sydney, has built three tDCS devices over the last 18 months, using schematics from the open source project OpenStim. (He’s also tried the Thync System, which is technically not a tDCS device, but a device that utilizes neurosignaling to trigger specific cranial and peripheral nerves.) He compares the effect to that of caffeine or nicotine; he feels an increase in concentration “about a quarter as intense as a cup of green tea,” while conceding the possibility of a placebo effect.
“All my friends think it’s too risky and refuse to try it, so I’m pretty much alone in experimenting with tDCS.”
Simpson-Young figures most tDCS experimenters are tech geeks looking to hack their brains. That description would fit Jimmy Hsu, a Bay Area entrepreneur and software engineer, who bought a kit from a company called the Brain Stimulator at the Quantified Self Conference and Expo in the summer of 2015. He used it on a semiweekly basis until that December and found it increased his focus, attention span, and “the speed in which you get into the ‘zone.’” He did have a brief spell “when gravity felt flipped upside down for a brief moment,” but generally speaks positively of the experience. Still, Hsu says, “All my friends think it’s too risky and refuse to try it, so I’m pretty much alone in experimenting with tDCS.”
Risk-averse consumers aside, a handful of companies are going to market with tDCS devices. Apexdevice, the Brain Stimulator, Foc.us, and Thync did not respond to interview requests, while the managing director of TCT Research Limited declined to continue our interview without an agreement to review the resulting article prior to publication. James Watson is the owner and operator of tDCS-Kit.com, which sells a $39.95 kit to “build” a tDCS device. “Finally, there is drug free (DIY) method to increase Concentration as well as relief for Depression, Anxiety and Migraines!” reads the copy at the top of the page, while a smaller sentence at the bottom reads, “tDCS-kit.com DOES NOT offer medical advice.”
Watson began the company three years ago in Fort Worth, Texas. He’s firmly in the enhancement camp: “I think, myself,” he says, “that we’re at the age of becoming more than a beast. I think manipulating energy to your brain is no different to changing your DNA—it’s just less invasive and cheaper.” Before he started building tDCS kits, he owned a company that made instruments for helicopters; he says he made the first 2,000 kits himself.
He’s adamant about the efficacy of tDCS in enhancing cognition. “There are a lot of studies that go every which way on this,” he acknowledges. But, he says, “there is an awful lot of stuff put out by the medical industry that is absolutely false. Look at the troubles we’re having with vaccines, every one of them has got something in there that has no reason to be in there.”
The lab’s principal investigator, Dr. Flavio Frohlich, who conceptualized and oversaw the study, says, “This is not a conclusive study saying tDCS does this or that, but it tells us that it is probably more complicated than we initially assumed; that it requires more work to understand under what specific circumstance tDCS enhances, or, perhaps in some circumstance also decreases, cognitive performance.” He points to still-open questions of what parts of whose brain are stimulated, how often, and how you measure the effects. Can tDCS enhance cognition? Possibly, Frolich says: “Do we know for sure yet? I don’t think so.”
He understands the urgency some people feel toward the technology—after all, bold claims are being made about it. “It is an exciting technology,” he says, “but please give us some time and opportunity to do the research, so that what we have for you will really give you what you’re hoping for.” Until we know better, he says, “I am gravely concerned about the unregulated use of this technology at this point beyond the medically supervised research setting, because we’re not there yet, we don’t understand it well enough.” He estimates it’ll require 5 to 10 more years of research before tDCS is approved as a treatment option for humans, though that’ll depend greatly on the application. Right now, treating depression is the most-studied application.
For James Watson, the delay of medical approval is a sign of corruption. “That’s what they always say,” he says. “That’s their answer to why they couldn’t cure cancer, couldn’t cure any of the diseases that were curable many, many decades ago.” He says “the whole thing is fixed,” describing a corrupt system that he says wants to keep simple solutions out of the hands of ordinary people. This is nothing but the same story I’ve heard out of the establishment my whole life: ‘Oh, we need more time to study it.’ Who’s going to study it: The morons in government? No. The people in universities that want to stay in the universities? No.”
Following our conversation, tDCS-Kit sent me its full DIY kit for personal experimentation, free of charge. Rather than strapping it to my head, I tested its components and electrodes with the help of an electrical technician and Peter Simpson-Young, at a MakerSpace in Sydney. The kit was tested with an oscilloscope, ammeter, and voltmeter. If used without a sponge and saline solution, the 2-by-2-inch “Long Lasting, Wet/Dry, Silver Cloth, foam-backed Electrodes,” as described on the website, were found unsafe for use, with the small, centered metal part of the electrode condensing the current into the center, causing too high a current density. The 1.25-inch self-sticking Electrodes (TENS electrodes) proved to have too high an electrical resistance; the device couldn’t run a current through them, meaning it would run very little current through any skin to which it was attached.
Hooked up to the technician’s forearm, the kit could output only between 0.12 and 0.20 milliamps of current; its website claims to provide a regulated 2 mA. The tDCS power supply unit contained only a 9-volt battery case, with no components that would allow the device to boost the current. “In our tests with both sets of electrodes, [the device] was never able to get to 2 mA, and was incapable of boosting the voltage to make it work as described,” said the electrical technician. (A cable running from the power supply unit contained regulator circuitry, but that would serve no function at the low current the kit produced.)
In short, this particular test kit did not work as advertised. Asked about the discrepancy between the measured current and that advertised on his website, Watson replied, in part, “Well, you better measure some more!” He continued, “Put anything negative in the article and I’ll sue you. You send that unit back and I’ll test IT!” He reiterated that the device puts out 2mA at the pins, suggesting that measuring from the pads—where the circuit would make contact with the body, and through which the current would pass—would give a different result.
The electrical technician who’d helped test the device responds: “Current is a flow of charge through a circuit, [it] doesn’t matter where you measure it.” Nonetheless, he says, “a 9-volt battery case is not a medical device. Nor is it functional, nor safe.”
Which brings us to the ethical questions behind tDCS devices, given what we know now about how (and if) they work. Dr. Anders Sandberg, of Oxford University’s Future of Humanity Institute, says, “The ethical issue is that many devices are sold either explicitly claiming they have particular beneficial results (or implicitly suggesting them, for example by pointing at real research results—not unlike how many nutrient supplements are sold).” A survey conducted of the tDCS subreddit and another DIY tDCS site found that of the self-selected sample, 11 percent use tDCS for treatment of medical conditions, 59 percent for cognitive enhancement, and 24 percent for both, suggesting that many users are looking to boost their brainpower, regardless of whether the science is settled.
“I have few worries about people with informed consent who try things on themselves, but I do think a fair number of people do not know what they are doing.”
Sandberg points out that even if the cognitive-enhancing effects were proven, that doesn’t mean tDCS devices are necessarily safe and effective, or that they can’t be used improperly, or that there aren’t still risks. “I have few worries about people with informed consent who try things on themselves, but I do think a fair number of people do not know what they are doing,” he says. “Of course, a lot of the experienced effects will also be placebo. So in the end, there is a real need for enhancement consumer information.”
Dr. Hannah Maslen is a research fellow in ethics at the Oxford Martin School at the University of Oxford; she’s currently researching the ethical, legal, and social effects of brain-intervention technologies. She says it’s reasonable for the scientific community to recommend that DIY tDCS users stop experimenting with the technology, even though such appeals are unlikely to be heeded. If the devices were regulated, with carefully vetted claims about their benefits and risks, then consumers could make informed decisions. “But at the moment,” she says, “manufacturers are on pretty shaky ground ethically given the likelihood that their claims mislead consumers and lead them to take risks they might not take if they had all the accurate information available.”
A lack of information, Maslen suggests, is the key problem. And she believes there could be more collaboration among scientists, ethicists, and the DIY community that’s likely to continue experimenting. “Ethicists can’t make assessments of reasonable risks and appropriate policies if they don’t have a firm grasp of the way the technology works and what the results of tDCS experiments really mean for effects on the brain,” she says. “Equally, it doesn’t seem appropriate to demand that the scientists do all the public education and engagement work, especially as there could be liability issues if they say anything other than ‘don’t try this at home.’”
Right now, she describes a kind of “Wild West,” where manufacturers sell devices that “claim to enhance pretty much every cognitive capacity in any person, with no qualifications or caveats.” That’s a highly improbable claim, Maslen says, even if some tDCS devices are helping some people. Ultimately everyone needs more information—scientists, ethicists, and consumers. “Consumers should be given a lot of freedom to choose what risks they want to take for what ends,” Maslen says, “but if they’re misinformed about the risks and effectiveness, they are unable to make an informed decision.” In the meantime, homebrew experimenters are taking the risks—and their brains—into their own hands.
Illustration by J. Longo.