Some medical professionals are vocalising their enthusiasm for a revival of neurosurgical psychiatric techniques, specifically Deep Brain Stimulation (DBS). But in light of the well-known controversial historic relationship between neurosurgery and mental health, how could the unique ethical issues surrounding researching and using this form of treatment be alleviated?
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During the 1950s and 60s, the prefrontal lobotomy was a new, promising, and widely used treatment for mental illnesses. Popularized by the now infamous duo of Walther Freeman and James Watts, the idea of psychiatric neurosurgery remains inextricably linked with the ethically-disastrous asylum era. Tens of thousands of surgeries were performed, often without informed consent or medical necessity, before the discovery of lithium and chlorpromazine started a new revolution.
Once again, the medical community has begun to speak of neurosurgery as a potential cure for mental illness. Direct Brain Stimulation (DBS), the procedure that's drawn the most interest, is much safer and far more precise than the lobotomies practised by Freeman and Watts, but not without ethical questions.
DBS involves the electrical stimulation of specific areas of the brain through electrodes directly implanted in the tissue. It requires surgery, during which small holes are drilled into the skull, the electrodes fed into the desired area, and a battery put underneath the skin. As a medical technology, DBS is closer to a pacemaker than to a surgery that cuts through a section of grey matter.
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The procedure was first developed to stop the tremors and other movement problems in Parkinson's disease, not treat mental illness. Alim Louis Benabid, a French-Algerian surgeon, discovered that his patients regained the ability to control their movement after inserting electrodes into an area of the brain associated with motor functions. Some patients would experience psychological side-effects like depression and hypomania, while others who also had mental illnesses saw those symptoms improve. These accidental side-effects were, in an oft-repeated story, psychiatry’s cue to begin investigating the technique.
Thirty years later, DBS remains an experimental treatment for mental illnesses, unable to be used outside of a research context. Researchers have little idea why it seems to work; its trials in OCD and depression have been encouraging. The trials have been small, and few have included control populations, so DBS' efficacy is still up in the air. Nonetheless, there's optimism that it could, in Walter Glannon's words, "fill the therapeutic vacuum left by the lack of development of new psychotropic drugs.”
However, it’s imperative to dampen excitement about so invasive an experimental procedure until thinking carefully about its ethical dimensions, especially given psychiatric neurosurgery’s history.
Placebo Effects and Sham Surgeries
The fact that DBS seems so major, so invasive, means that significant placebo effects are responsible for the encouraging results. The knowledge that an electrical current is flowing directly into one's brain can produce an extremely strong expectation of their symptoms improving and, perhaps, cause that improvement.
Controlled experiments are the only way to tell whether a placebo effect is at play. In such a study, half the participants receive treatment, and half don't, without being told who is who. Since DBS involves surgery, half the participants of a controlled trial will undergo a fake, or sham, surgery that involves drilling holes in the skull and all the rest. The only difference is that the control group's devices are never turned on.
The ethical standing of sham surgeries is contentious. For some, fake surgeries are obviously unethical—a normal placebo is a sugar pill, but surgical placebos could be very harmful. "Performing a surgical procedure that has no expected benefit other than the placebo effect violates the ethical and regulatory principle that the risk of harm to subjects must be minimized in the conduct of research," writes Ruth Macklin.
Not doing sham surgeries may also have harmful consequences. Another surgical procedure, arthroscopic surgery to relieve arthritic knee pain, illustrates one of them. Patients got the surgery—a small incision in the knee's joint—for decades before any placebo-controlled trials took place. When they were finally done, researchers realized that patients hadn't been benefiting from the surgery. Were DBS to enter common practice without controlled studies, many people with depression, OCD, and other mental illnesses could similarly receive risky surgeries for no reason.
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Another potential outcome of foregoing controlled studies is DBS never moving forward—not because it doesn't work, but because we can't tell if it works. Supposing it does work, those who could have benefited from a novel treatment, and particularly those suffering from a case of mental illness that resist current medications, would be deprived of it.
In psychiatric settings, ethical problems surrounding informed consent always loom large. Involuntary treatment and detention are still controversial, and the potential return of neurosurgery to mental health wards only sharpens the issues. Nearly every country in the world has legislation setting outs criteria for when psychiatric patients are considered incapable of making medical decisions. If DBS proves to be effective and enters standard practice, the status quo would allow psychiatrists to order the surgery for 'incapable' patients regardless of their wishes. Whether or not one believes coerced treatment is always unethical, the jump from forcing someone to take a psychotropic drug to undergo brain surgery seems significant.
Some ethicists would argue that the difference between surgeries and medications are irrelevant to issues of consent. After all, medications directly affect the brain, albeit through the bloodstream rather than the skull. Glannon, for instance, believes that surrogate decision-makers should be able to consent to the treatment on a patients’ behalf, just like in other psychiatric circumstances.
However, there are precedents for protecting consent to higher degrees when more invasive treatments are under consideration. In Australia, for example, there are additional protections for patients who may be given ECT involuntarily; each case automatically goes before the country's mental health tribunal, unlike other treatments. Their Mental Health Act recognizes that a treatment's invasiveness changes the ethical calculus surrounding it.
There have been many reports that DBS can cause significant and persistent changes in personality. Françoise Baylis writes, "whether the effects of DBS are positive or negative, physical or psychological, transient or permanent, they can have a profound impact on personality, on familial, marital, social, and professional relations." The prospect of technology altering what it feels like to be oneself threatens a person's 'narrative identity,' or, in other words, the cohesion of the story they tell about themselves.
These types of changes are not uncommon; surveys of people caring for Parkinson's patients who've been given DBS treatment have found that caregivers both perceive personality changes and find them hard to deal with. One much-discussed case features a 62-year-old man with Parkinson's disease, whose DBS implants restored his ability to move when turned on but produced a manic state so severe it required constant supervision in a mental health ward. In a real sense, he was two different people when his device was on or off. When given the choice of whether to continue DBS, he chose to be able to move but live with his altered, manic personality. It's uncertain whether many people undergoing DBS for psychiatric conditions would be granted this choice.
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There's been little research examining DBS's effects on personality when used for psychiatric conditions, but it would be surprising if there were none. Some people suffering from severe mental illnesses might be willing to face personality changes to lessen their symptoms, while others would not. However, to make that choice, both patients and psychiatrists need to understand the treatment's impact on personality. Only then can, in Baylis' words, "a more robust and meaningful informed consent process that incorporates patients' views of personal identity and what counts as a risk or benefit" be built.
I haven't come to any firm conclusions while examining these issues because, in medical ethics, convictions should come in light of scientific evidence, not before it arrives. Using DBS to treat mental illnesses is still experimental, so each use of the technology comes in the context of an investigation into its safety and efficacy.
Scientists have found some areas of the brain that seem to be associated with particular illnesses. Still, they don't know the exact role of, say, the nucleus accumbens in depression, nor the effects of electrically stimulating it. These uncertainties mean that DBS still has a long way to go before it is ready to enter psychiatry's repertoire. Daniel R. Cleary and his coauthors sum up the situation, “the continuing challenge inherent in neurosurgery for psychiatric disorders will be to balance the urge to offer promising (but in truth still investigational) operations for treatment-resistant disease, with the need for careful evaluation of underlying physiology and outcomes data.”