Photos: Ybrain Band of Aid: Ybrain’s transcranial direct-current stimulation headband [top] is designed for home use. A doctor programs prescriptions, including amperage and duration of treatment, into the device’s processing modules [bottom].
A doctor’s prescription for clinical depression could one day sound like this: In the comfort of your own home, slip on a brain-zapping headband a few times per week. For 20 minutes, it will send a tiny stream of electricity through your brain.
The treatment would be delivered by a user-friendly type of brain stimulation called tDCS (transcranial direct-current stimulation). This mind-altering technique has become a hot topic in neuroscience research over the last decade, and it’s now beginning the transition from lab to doctor’s office.
In South Korea, the startup Ybrain is betting that its tDCS headband, specifically designed to treat depression, will be the product that brings the electric treatment into the medical mainstream. Ybrain founder and CEO Kiwon Lee expected his device to receive regulatory approval in Korea in February. He plans to roll out the device in 70 Korean hospitals this year to reach thousands of patients with clinical depression. The company will use data from all those patients to build a case for approval first in Europe, Lee says, and then in the United States, where the regulatory requirements are most stringent. “After one device is approved [in the United States], it will be seen as a mainstream treatment,” he says.
tDCS is considered an exciting new possibility for clinical use because the gear is cheap, portable, and easy to use. The headsets press electrodes against particular locations on the scalp to channel a few milliamperes of current through a specific brain region, and they can be powered by a 9-volt battery. Last year there were nearly 700 papers published about tDCS, with studies on every topic imaginable: Researchers have experimented with physical rehab for stroke patients, memory improvement for people with Alzheimer’s disease, and craving reduction for smokers and alcoholics.
Ybrain may not be the first to enter the all-important American market; New York City–based Soterix Medical may beat it. Soterix chief technology officer Abhishek Datta says that its tDCS system for depression was approved for clinical use in Europe in late 2015, and he says more than 30 European clinics now use it. The company is currently pursuing approval in Canada and the United States. At the moment, the Soterix treatment is not quite as user friendly as Ybrain’s. Although the company offers a take-home version of its tDCS system, Datta says most European patients are receiving their stimulation at a clinic under a doctor’s supervision.
Ybrain hopes its slick, consumer-friendly design will make at-home treatment the norm. “It’s designed for home use,” says Lee, “so physicians can electronically prescribe the device and patients can bring it to their homes.”
To make the medical gadget easy to use and fail-safe, Ybrain’s designers kept it simple. “The device has just a power button, no interface,” Lee says. “The patient turns it on and puts the device on their head, and it automatically starts the stimulation based on the doctor’s prescription.” If the doctor prescribed one 20-minute session per day at 2 milliamperes, for example, the gadget wouldn’t allow more stimulation than the prescribed limit.
Though companies are pushing ahead with commercialization, many scientific questions must still be answered about tDCS. Neuromodulation experts agree that it can alter the brain in meaningful ways—but they’re still figuring out which medical conditions will truly benefit from these alterations. An article recently published in the journal Clinical Neurophysiology reviewed the evidence on tDCS effectiveness across a range of disorders; for most, the article said that there haven’t yet been enough rigorous trials to draw conclusions.
However, that article singled out tDCS treatment for depression as “probably effective.” Considering the World Health Organization’s estimate that some 350 million people around the world suffer from depression, many researchers and clinicians think that depression might be the first killer app for tDCS.
Andre Brunoni, a neuroscientist and psychiatrist at the University of São Paulo, provided strong evidence of tDCS’s utility for depression in a 2013 study he coauthored that compared tDCS to a standard antidepressant medication. That study found electric and pharmaceutical therapies to be equally effective, and it found that patients who received both treatments together fared best of all. But Brunoni says he’s not ready to forge ahead with tDCS in his clinical practice; he’s still waiting for answers to many crucial questions that will define its practical use. “We don’t know the best ‘dose’ to use for tDCS,” he says. “What’s the best amount of current to use? What’s the optimal number of sessions? There are a lot of parameters to explore.”
If such issues are resolved, Brunoni says tDCS may offer several advantages over both antidepressant drugs and another device-based depression treatment, transcranial magnetic stimulation (TMS), which is performed using a large and comparatively expensive machine at a clinic. Because tDCS treatment is relatively cheap, Brunoni says, private medical plans would likely prefer it. Safe and reliable devices from companies such as Soterix and Ybrain will allow home use “with almost zero risk,” he says. And treatments can be short-term, beginning with an intense phase—for example, two weeks of daily sessions—followed by less frequent “maintenance” stimulation sessions. Brunoni says this timing offers a big advantage over antidepressant drugs, which require treatment for at least nine months and can cause unpleasant side effects throughout that period (like weight gain and sexual problems).
While hopes are high for tDCS depression treatments, some experts are cautious. Mark George, an eminent neurologist and psychiatrist who directs the Brain Stimulation Laboratory at the Medical University of South Carolina, in Charleston, says he’s not yet ready to prescribe tDCS to his clinically depressed patients. He invokes Hippocrates: “First, do no harm.” While there’s ample evidence that tDCS is safe when used correctly, George notes that physical safety isn’t the only consideration. The depressed patients he sees are desperate, despondent, and looking to him for salvation.
“Hope is fragile,” George says, “and you want to be very careful with what you throw out there for your patients. You want to go with your best shot. And right now, I don’t see tDCS as your best shot.”