Psychiatry's Most Promising New Treatment Is a Pacemaker For the Brain

At the end of One Flew Over the Cuckoo's Nest, a young Jack Nicholson lies in bed with two fresh centipede scars across his forehead. His face is expressionless, an open-mouthed stare, his entire body broken into absolute submission.

Forty years later, it's still one of the most iconic depictions of lobotomy—the procedure of surgically removing or scrambling parts of a person's brain to alter their mood, thoughts, and behaviour.

When psychiatric drugs emerged in the 1950s—and with it, a new era of modern medicine—the public's conception of lobotomies and ECT crystallized into the old-fashioned asylum nightmares we know today (see: a 2008 horror movie quite literally titled Asylum). To American cinema, surgical knives and electrical shocks became psychiatry's emblematic tools for social control.

Even today, our perception of psychiatry remains clouded by the procedure's gloomy legacy, and by harrowing scenes of electroconvulsive therapy (ECT). In Cuckoo's Nest, Nicholson's character undergoes ECT in a scene that frames just his face, disfigured in pain. The audio track consists exclusively of groaning.

It's ironic, then, that these same tools form the basis of one of modern day psychiatry's most promising emerging treatments. Deep brain stimulation (DBS for short) involves surgically inserting two electrodes deep into the brain, which deliver regular electrical pulses to a specific region. Researchers in the field compare it to a pacemaker—an electrical brain implant for stabilizing emotions and thoughts.

DBS has actually been around since the 1980s. It's an established treatment for movement disorders such as Parkinson's disease, and has also been used to treat chronic pain—both domains of physical medicine. But for the first time in 2003, a group of researchers in Toronto conducted a study of psychiatric uses of DBS in six people with treatment-resistant depression. On average, they'd been depressed for twenty years.

Dr. Peter Giacobbe, a Toronto psychiatrist, joined the group in 2004, and remembers the excitement that accompanied that first study.

"It was really a 'proof of concept' kind of study. Is it safe? Do people get better? Is there any reason to continue this line of inquiry?" Giacobbe told me in an interview.

The surgery itself takes four to five hours. Surgeons pinpoint their target region based on a 3D MRI reconstruction of the patient's brain, and drill two burr holes the size of a nickel into the skull as an entry point. The patient then lies awake as the surgeon advances the two electrodes to their planned locations. The patient's emotional and cognitive responses are monitored, and the electrodes shifted accordingly.

The second part of the operation—this time, under general anesthetic—involves inserting the battery-powered implantable pulse generator (IPG) under the patient's collarbone. A wire from each electrode exits the skull through the burr holes, which are capped and cemented in place. The wires snake down the sides of the scalp and neck, tunneled under the skin, to hook up to the IPG that controls the "dose" of electric pulses delivered to the brain. Once the patient heals, the implants can stay in place for years—until the battery in the IPG runs out, requiring a 30-minute procedure to replace it.

In the Toronto group's study, four of the six patients had experienced major reductions of their symptoms two months after the operation, and their improvements held for a year. Of course, two-thirds success doesn't herald a panacea, but neither have psychiatry's mainstays of psychotherapy and medication.

That initial paper, published in 2005, now has over 2,000 citations. "Once it got published, we had inquiries from around the world—people saying 'I'm really depressed, can you evaluate me?' It took off," said Giacobbe.

Today, multiple centres around the world conduct DBS research, with five groups in Canada and more in Europe and the US. People with DBS have seen a sustained reduction in their symptoms for over a decade, and researchers have extended its psychiatric applications to study obsessive-compulsive disorder, bipolar disorder, and anorexia nervosa. In Toronto, the longest-standing center for DBS research, there are 58 current patients who have undergone the procedure.

While past research in this area tackled issues of safety and effectiveness, newer studies have sought to find out just how well DBS works. The results could determine whether DBS can be considered an established treatment, and not simply a last resort.

"What is the right dose? What is the best combination of stimulation with talk therapy, psychosocial treatments, and medications?" Giacobbe said.

There is evidence from the Toronto group, for example, that DBS might make the brain more receptive to other treatments. This finding is based on an ongoing line of research in Toronto, using animal models. As Giacobbe explained, their findings showed that certain types of medications that didn't work well originally were actually enhanced after receiving DBS.

There's also the issue of establishing the best location for the electrode, and determining which other illnesses might benefit from electrical stimulation. In fact, DBS research has begun to break down diagnostic boundaries, based on evidence that stimulating the so-called "depression center"—the subgenual cingulate cortex—might also improve symptoms for people diagnosed with bipolar disorder and anorexia nervosa.

"We don't think the brain reads DSM-5. So we're looking at things transdiagnostically," said Giacobbe. In other words, while traditional psychiatric research has approached diseases as separate entities, researchers have begun shift their focus to symptoms that cut across diagnostic labels. The logic is that even though diagnoses like depression and anorexia can appear quite different, they might hold elements in common that can be localized in the brain, and targeted for treatment.

Despite its success and safety—the technique is a long ways away from the frontal lobe scramble that made the lobotomy notorious—DBS advocates have had to reckon with the shadow cast by earlier forms of psychosurgery, such as lobotomy. Language shapes attitudes in a powerful way, and the subtleties of DBS's framing rely on language such as "pulses" rather than "shocks," and in deft comparisons to the trusty pacemaker.

The rhetoric of DBS hasn't gone unnoticed in academia. Jennel Johnson, a professor at the University of Wisconsin-Madison, studies the rhetoric of science, medicine, and public culture. In a 2009 article, she explored the strategies DBS proponents use to negotiate the link between DBS and its predecessor, the lobotomy.

"For DBS advocates, establishing the relationship between these two treatments is not just a matter of telling a history," wrote Johnson. "It involves crafting persuasive arguments for the lineage of DBS that address, in some way, the powerful memory of lobotomy."

But after twelve years, dozens of surgeries, and a rhetorical thrust to boot, the most interesting question about DBS remains unanswered. Namely, scientists still don't really know how DBS works.

"What is the actual active ingredient?" mused Giacobbe. "That's a question that people don't actually know right now."

Modern Medicine is a series on Motherboard about how health care and medical technology can move forward so rapidly while still being stuck in the past. Follow along here.