One could be forgiven for feeling wary rather than celebratory this October when Stanford University neuroscientist and psychiatrist Karl Deisseroth, along with two German scientists, received the Nobel Prize for inventing a new, invasive brain technology dubbed “optogenetics.”
After all, the last time a psychiatric treatment garnered a Nobel Prize for Physiology or Medicine was in 1949—for the lobotomy technique of severing the arteries into the brain’s frontal lobes. The award further boosted excitement among psychiatrists worldwide, who ultimately administered lobotomies to tens of thousands of people (often by, infamously, hammering an icepick through both eye sockets) as a “calming treatment” for hundreds of different mental and emotional conditions. Mainstream psychiatry later moved on from lobotomies with the emergence of new drugs. But protest campaigns led by family members of lobotomized patients continued for decades as they tried (in vain) to get the Nobel Foundation to rescind its award for a practice that had killed an estimated 5 percent of patients and left countless others permanently stripped of major emotional, mental, and functional capacities.
So, in 2026, is optogenetics biological psychiatry’s long-sought breakthrough for understanding and rectifying dysfunction in the mechanisms of the brain? Or is it another damaging, dangerous tool? Reading some of the leading researchers in the field reveals that it could be a bit of both.
Karl Deisseroth: From Poetic Emoting to Policing Emotion
To understand the roots and likely future of this “revolutionary” new brain technology, it helps to first understand a little about its founder and leading developer.
In his book, Projections: A Story of Human Emotions, and in a wide-ranging, three-hour interview with computer scientist Lex Fridman, Karl Deisseroth shows his appreciation for both scientific and artistic ways of viewing the human condition.
Alongside his neuroscientific research, Deisseroth works in both hospital inpatient and private outpatient psychiatric practice, and writes literary nonfiction. He believes in the value of talk therapy, is interested in extreme states of consciousness, frequently fuels his thinking with poets and novelists such as Jorge Luis Borges, Toni Morrison, and James Joyce and, when describing his conversations with his patients, uses words like “empathy” and “communion.”
Yet Deisseroth also writes that he was “trained to see brains as biological objects, as they indeed are.” He describes many of those same patients as having “diseases” or “disorders” of the brain, and not infrequently authorizes that they be involuntarily committed and forcibly drugged against their protests. And he appears to have no serious sociological or scientific critique of common psychiatric research and practices. For example, he regularly discusses the lack of reliable lab tests in psychiatry to verify any diagnoses or positive emotional impacts from treatments, yet he also describes electroconvulsive shock therapy (ECT) as “very effective” for depression—with no acknowledgement of the dearth of quality scientific evidence supporting such a view. He describes lithium as “highly effective for bipolar”—despite broad scientific questions about such claims. And he says studies in twins have proven that depression, bipolar, and other mental disorders have major genetic drivers—with no acknowledgement of the scientific gaps and biases common in twin and other behavioral genetics studies.
One of many stories from Deisseroth’s book that vividly illustrate these seemingly contradictory tendencies is that of a 67-year-old retired insurance executive he calls Alexander. After witnessing the 9/11 attacks on the World Trade Center, the man becomes swept up in a whirlwind of new interests and activities, hoping to find ways to help his country. Alexander’s family is worried about these dramatic changes and get into conflicts with him, but Alexander himself regards what’s happening as exciting, positive, a revitalizing surge of youthful energy, and a new, more meaningful lease on life. Deisseroth reflects on how a similar experience came over him after a rush to escape an armed robbery left him hyper-energized for weeks. Deisseroth also relates Alexander’s impassioned convictions and behaviors to those of literary figures, historical leaders, and mythical heroes of extraordinary achievements, and to an evolutionary need to respond intensely to threats and challenges that’s part of “a common heritage of humanity across cultures and continents” and “an elevated expression of what a human being can be.” He suggests Alexander is going through a deep, personal “metamorphosis.”
Unfortunately, Deisseroth then tells us, Alexander was “born in the wrong time and place” to harbor such intense energy. Deisseroth diagnoses Alexander as having “mania” and locks him up and drugs him against his will with tranquilizing antipsychotics. Alexander’s wife is relieved. But Deisseroth admits that this “normalizing” of Alexander was “not a clear-cut win”—even a year later, he writes, Alexander was no longer “manic,” but seemed “glum” in his inconsequential retired life and “still did not understand why we had acted as we did.”
In virtually every other story, Deisseroth’s empathy for his patients comes with a similar hard limit—his interest in them seems less a “communion” of equals than the fascination of a zookeeper for his caged animals. Could this be a cautionary metaphor for where the field of psychiatric optogenetics is headed?
What optogenetics is and how it works
For a breakthrough technique in brain research, the basics of optogenetics are nevertheless surprisingly easy to understand.
In a single-celled alga, German researchers isolated a protein, called channelrhodopsin, that made the alga move towards light. Deisseroth developed a technique whereby the gene that produces channelrhodopsin is carried by a virus (a “viral vector”) and functionally embedded into selected brain cells, after which the firing of those brain cells can be turned on or off by exposure to a light source implanted in the brain.
Developed in the early 2000s, optogenetics was a massive leap in precision beyond brain scans and electrical brain stimulation devices for studying and changing the activities of specific brain cells and cell networks and circuits. Optogenetics has exploded in popularity, by 2022 engaging thousands of research institutions in over 51 countries, while genes, methods, and techniques have multiplied.
So far, most of the brain research has taken place in living mice—but theoretically, there’s nothing stopping it from being implemented in human brains. And though linking mice behaviors to imagined human-like thoughts, feelings, and experiences is an inexact science at best, still, the discoveries have been striking.
Using optogenetics, researchers have been able to isolate and control mouse brain circuits that switch on and off fear and anxiety reactions, addiction behaviors, and social avoidance, implant false memories, block or enhance memory formation, and even break down into component brain circuits more complex behaviors such as how mice care for their young.
In his book, Deisseroth uses the word “eerie” to describe witnessing how mouse brain states and behaviors “could be added to or subtracted from” in these ways—such as making a mouse freeze with apparent fear over nothing, and then promptly become active again.
Researchers believe this ability to turn cells on and off may have many applications—such as for stopping tremors, controlling epilepsy, healing deafness, curbing neuropathic pain, restoring bladder or bowel dysfunction after spinal cord injury, and treating amyotrophic lateral sclerosis. Already in one case, a blind person, through optogenetics on his eye and the aid of specially engineered goggles, partially recovered vision.
All of those applications offer cell targets in more safely accessible parts of the human body—but it’s the possible brain applications that animate Deisseroth the most. In a paper specifically about using optogenetics in psychiatry, Deisseroth and other researchers state that the main goal of experiments on animals is to identify “neurobiological mechanisms” of mental disorders and then target these in humans with new “pills that non-invasively cure or ease the symptoms of mental illness with minimal undesirable side effects.”
They add, though, that the “heavy burden” of mental illnesses “demands” that entirely new treatment options also be developed besides drugs—including, possibly, “optical tuning” of the brain through direct application of optogenetics on humans. They suggest, for starters, using optogenetics to tackle aspects of drug addiction, depression, anxiety and PTSD.
In his book, Deisseroth writes with enthusiasm about using “cellular precision” in manipulating “brain circuits” to rectify “human frailty,” ease human suffering, and cure the “causation” of psychiatric disorders.
However, pressed by Fridman in his interview, Deisseroth becomes more circumspect. He explains that optogenetics scientists may be able to “turn up or down” specific behaviors linked to specific brain circuitry—such as a particular compulsive activity—but acknowledges that it remains mystifying how or why most behaviors truly arise. Even in mice, he says, the “choice” to take any particular action appears to mysteriously “start” in innumerable places “all across the brain… all at about the same time.” Consequently, optogenetics interventions won’t truly be addressing the root causes of people’s suffering any time soon but, like psychiatric drugs currently do, Deisseroth says they could be used to “treat symptoms.”
This admission raises a spectre: An optogenetics intervention might well be experienced—by humans and mice—as an irrational, altered reality, where a behavior feels uncontrolled and completely disconnected from what’s perceived through the senses and desired through the thoughts. What would this kind of disassociation between desire and action, between self and reality, repeating over and over again, do to a vulnerable mind?
And what of the potential biological risks and harms?
The risks of optogenetics
Optogenetic brain interventions involve both viral delivery, through injection, of a genetic alteration to selected brain cells, and an implant to deliver light directly inside the brain. This has never been tested on humans.
Viral gene therapy alone is hazardous—experiments on humans have sometimes triggered life-threatening responses, especially from immune system reactions, including deaths.
Certainly, some leaders in the field are openly grappling with the hazards, uncertainties, and ethics of optogenetics.
In one paper, a team of British researchers summarize concerns about possible adverse effects of optogenetics, and identify a host of “currently unanswered questions.”
The initial injection will have to carry a substantial load of the virus and gene, because repeated deep-brain injections are simply “not feasible,” the researchers state—and that makes potentially dangerous immune responses even more likely. Cellular toxification or damage and instigation of brain tumors are also all possible.
Patients will have to accept hosting a “non-human” gene and protein inside their brains, they write, and this, along with any associated impacts, will be permanent and irreversible.
The light-producing devices must be implanted deep enough in the brain to reach the target area. Even very slight amounts of heat generated by the light could be extremely harmful to surrounding cells. The implant can damage the underlying brain tissue during placement or subsequent movement, while also potentially making it more difficult to detect these damages due to common implant materials disrupting MRI scanning. And the long-term effects of light itself on the cells of an enclosed brain are utterly unknown.
In a 2025 Nature Science paper, Swiss and American researchers, including Deisseroth, note that additional unknown, long-term risks exist due to the comparatively short lifespans of the mice that have been so far tested, and the comparatively much lower threshold for the activation of immune responses in humans.
The human experimentation question
The Swiss and American researchers write that testing these potentially harmful techniques in more-similar non-human primates such as monkeys comes with “considerable regulatory and ethical burdens.”
The British researchers point out that new drugs are always clinically tested for safety in healthy human volunteers, but optogenetics is so hazardous that “it is ethically out of the question to deliver both a permanent gene therapy and to implant a novel device” into any healthy human.
Furthermore, because the brains of mice are hardly perfect analogues for much larger and more complex human brains, it’s questionable how much—if any—of the existing research learnings will translate to humans. Therefore, the British researchers note, “there can be no guarantee” that the first human groups submitting to optogenetics studies would get any clinical benefit at all.
In spite of this, neither team of researchers calls for banning experiments on humans. On the contrary: Noting that new medical devices (which aren’t as tightly regulated as drugs) are often used in trials on ill people with relatively little prior safety testing, the researchers lobby for jumping directly to experimenting on people who have severe physical or mental illnesses.
Enter the rationalizations
Both research teams acknowledge serious ethical concerns with such human experiments—albeit they do so in ways that can seem more worrying than reassuring.
The Swiss and American researchers write: “Direct optogenetics in the brain can alter cognitive processes such as mood, motivation and memory, as well as fundamental survival drives common to all mammals—including anxiety, fear, hunger, thirst, reward-seeking, aggression, mating, nurturing and parenting. Together, these capabilities underscore the profound ethical implications of optogenetics for altering human behavior, desires and decisions. The stakes are high…”
They propose “complete transparency” with patients, tight regulatory oversight, long-term monitoring of impacts, and “fostering a collaborative ethical discourse—encompassing scientists, ethicists, legal experts, patients, families and other public stakeholders.” They further pledge to “champion the principles of voluntariness” and safeguard “freedom of thought.”
Along the way, though, they invoke the somewhat Orwellian-seeming notion that even prospective patients with purportedly diseased, disordered, dysfunctional minds must nevertheless by all means be granted the “cognitive liberty” to submit to psychiatrists’ potentially deadly experiments in thought control.
The British researchers follow a similarly contorted line of reasoning to push for experiments on humans.
They note that, for example, a “schizophrenia patient suffering severe side effects to their medication” might likely welcome an optogenetic intervention as an alternative. However, because optogenetics is so nascent, they write, “there cannot be any suggestion of benefit put forward” to these patients—even though, of course, they themselves have already enticingly suggested optogenetics could produce fewer side effects than medications.
Establishing with a patient a correct “understanding” of the “risk/benefit balance,” they write, allows for the vital “informed consent” that will move ethical human trials forward—even though, again, they themselves acknowledge that the true risk/benefit balance is impossible to know and the “vulnerable” patients most willing to try optogenetics “may have an impaired ability to give informed consent.”
No mentions of coercion or power
And the most frightening part of these ethics discussions is what’s going unsaid. These researchers’ apparent collective naivete about the actual economic and socio-political context of their profession—whether from ivory-tower ignorance, willful delusion, or deliberate obfuscation—is profoundly disturbing.
For example, yes, many medical devices often are introduced into markets and used on ill humans without important kinds of safety and effectiveness testing first—however, as a recent Government Accountability Office report summarized, this practice has contributed to millions of injuries and tens of thousands of deaths in the U.S. alone in just ten years. Indeed, electroconvulsive shock therapy (ECT) devices are arguably one of these—they’ve never been tested by regulators for safety or effectiveness despite widespread reports of permanent memory loss, heart attacks, and other serious adverse impacts.
Countless psychiatric patients were promised long-term support for submitting to treatments with experimental Deep Brain Stimulation (DBS) devices but, across two decades, such patients have been repeatedly left with dangerously malfunctioning and degenerating implants in their heads and no support from government regulators, health insurers, research institutions, or doctors. And the excitement and fervor among optogenetics researchers that’s tangible in their writings—now amplified by the Nobel Prize—suggest optogenetics has the potential to have impacts at exponentially larger scales than DBS.
Meanwhile, none of these papers discuss the heightened risks for patients created by the profit-driven motives that are widespread in psychiatric research, even as hundreds of commercial optogenetics patents have already been filed.
They don’t discuss the misleading coerciveness about the alleged effectiveness of psychiatric treatments that’s endemic in public communications from industry advertisers and physicians, health websites, and even health regulators.
They don’t discuss the high and rising rates of uses of force against psychiatric patients, nor the fact that it’s not uncommon for extremely vulnerable psychiatric patients to be coerced into risky studies.
Either all of these researchers are unaware of these problems in their own profession, or, even in the context of specifically discussing psychiatric ethics, they simply don’t consider the ongoing, systemic, mass-scale harms of modern psychiatric power and coercion—nor the victims of them—to be worthy of mention.
In the end, it’s unclear which is worse—but it proves our society has nothing close to a safe environment for optogenetics trials on humans.
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Top image © The Nobel Committee for Physiology or Medicine. Ill. Mattias Karlén