by Ruqaiya Mithani
art by Qingyang Meng
Mental health awareness and its discussion in both academic and colloquial circles have undoubtedly increased in recent years. More people each day are beginning to understand what mental illness is and the kind of impact it can have on those around them. What hasn’t changed as much though, is how we assess the treatments for mental illness that are currently available on the market. Mental illness treatment, much like treatment for physical ailments, does not have a one-step solution. For physical conditions, we can observe when medications aren’t working. Mental illnesses, however, often don’t come with the same measurable differences. Concerns around the side effects and efficacy of drugs that target mental illness easily go overlooked, leaving those who rely on them feeling frustrated, trapped, and hopeless. The need for effective treatment, although clear, has not been met by existing drugs and treatment options. But with advancements in artificial intelligence combined with current therapies, a new, groundbreaking remedy may be the future of treating mental illness: neural implants might be the solution we are looking for.
The prevalence of mental illness has exploded over the past two decades. With this increase in diagnoses, there has been a corresponding rise in the prescription of drugs to treat these illnesses, particularly in younger populations [1–3]. In a study observing the trends in antidepressant prescriptions in the United Kingdom, the number of prescriptions has more than tripled in the past 20 years, particularly in the SSRI (selective serotonin reuptake inhibitors) class of antidepressants [4]. A similar trend was seen among college students in the United States and Canada, with the percentage of students taking antidepressants jumping from 8.0% to 15.3% between 2007 and 2019 [5]. This increase in prescriptions, however, also comes with unintended side effects associated with their respective drugs.
These side effects can be seen in medicines like SSRIs [6–8]. SSRIs, a popular treatment option particularly known for its use to treat depression, currently carries claims of being widely prescribed because they have the fewest side effects [8]. Despite these claims, SSRIs have been reported to cause common adverse effects including nausea, insomnia, and drowsiness [9]. Additionally, they may lead to lesser-known but riskier effects such as serotonin syndrome, a condition characterized by an increased activity of serotonin that can lead to neuromuscular hyperactivity and various psychological detriments [10]. These symptoms and the plethora of others are more than enough to disrupt normal function and create additional problems despite attempting to solve others.
So now we arrive at somewhat of an impasse. Mental health diagnoses are rising, yet the current treatment options are insufficient. Where do we turn to? Neural implants might be the alternative treatment answer we are looking for [11]. Leading biotech companies such as Inner Cosmos and the infamous Neuralink have begun experimenting and producing hardware that could eventually develop into treatments for mental illness. These companies have made particular strides in aiming to treat depression through innovative implantable hardware instead of the administration of drugs [12].
Where it All Began
While neural implants are the most recent revelation in mental illness treatment, approaches to ameliorating the symptoms of mental illnesses have been rapidly changing and progressing for decades. For instance, the standard treatments for depression in the 1800s included trephination, purging, and bloodletting as derived from early beliefs that mental illnesses were caused by demonic possession, imbalances in bodily fluid, or issues with the human skull [13].. The use of these physical methods continued with the development of asylums and “treatment” centers that were largely focused on removing mentally ill people from neuronormative society and isolating them. The 1950s saw a boom in the discovery and use of drugs, particularly antidepressants, to counter the drastic rise in depression diagnoses [13]. Drugs such as chlorpromazine and similar antipsychotic medications were the first widely prescribed for depression with psychotic symptoms, such as delusions and hallucinations [14]. The next big discovery in treatment came with monoamine oxidase inhibitors (MAOIs), such as iproniazid, which supposedly produced a mood-elevating effect through the inhibition of monoamines and production of additional serotonin and norepinephrine in the brain [15]. The use of monoamine reuptake inhibitors (MAUIs) like imipramine, gained traction during the 1960s [14]. As MAUIs grew in popularity, the use of tricyclic antidepressants (TCAs) also became common. TCAs caused patients to become more socially active and decreased fatigue [16]. Tricyclic drugs became associated with treating depression symptoms, but caused additional symptoms of dizziness, memory impairments, and drowsiness [16]. By the 1990s, selective serotonin reuptake inhibitors, or SSRIs, became the most popular prescription for depression. Research at the time implied that issues with the serotonin system contributed to depression, encouraging use of SSRIs [14]. In spite of their popularity, for many people suffering from depression, these pharmacological treatment options often failed to combat the effects of their depression. Enter neuromodulation therapies [17].
Neuromodulation is broadly referred to as interfacing with the nervous system using electrical, electromagnetic, chemical, or optogenetic methods present through technology [18]. Some neuromodulation techniques specifically used to treat depression include transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and trigeminal nerve stimulation (TNS), which activates the nerve responsible for providing sensory innervation to the face [19]. TMS uses either singular or multiple magnetic coils or magnets and the magnetic field it creates to noninvasively stimulate brain areas to notably treat major depressive disorder (MDD) [19]. DBS works similarly but involves a more invasive approach with inserting electrodes into target locations and then delivering electrical stimulation to see expected results [18]. TNS targets the trigeminal nerve and stimulates it based on evidence that it can improve depression in test subjects [19]. Neural implants use these methods, sometimes in combination with oral medication, to craft a more effective way to treat depression, especially in patients for whom other therapies have not been effective.
The Development of Neural Implants
Neural implants are some of the newest developments in depression treatment, with many pioneers of these devices receiving the go-ahead to begin human trials and start the FDA approval process. One of these groundbreaking companies is Inner Cosmos, a biotech company that recently implanted its neural device, the “Digital Pill” into its first patient [20]. This specific implant was designed to limit the risks associated with surgical treatment options for depression, and is about the size of a fingernail––the smallest neurostimulation device available on the market [21]. Their “Digital Pill” works in two parts. The first piece is the actual implant, which sits adjacent to the skull, under the skin, while the second is a pod that snaps onto the implant through the hair and delivers small electrical pulses [20]. These pulses are delivered based on what the implant senses about the current state of the brain and how the physician in charge wants to treat their patient’s depression [20, 21]. These implants work with sensors that track neural activity through electrical signals. The signals are used to compute neural changes occurring due to depression, and the implant will then stimulate brain areas associated with these changes in order to counteract them. [22]. This minimally invasive technology seeks to replicate the routine of taking a pill without the hassle of figuring out dosage or mixing different pills while also providing immediate results. With its first and second human trials underway, expectations for its performance are set to a high standard.
While neural implants developed by Inner Cosmos have had favorable outcomes, not all companies developing these implants have seen the same positive progression. Neuralink, a biotech start-up owned by Elon Musk, has been investigated for its experimental trials in monkeys, and heavily criticized by various communities, such as the Physicians Committee for Responsible Medicine, for violating laws against unnecessarily harsh or endangering treatment of animal test subjects [23]. The Neuralink implant is currently being developed to allow patients to control technology with their minds, including tasks like typing words and sentences, with possible future expansion into use as a treatment for depression and other mental illnesses. However, before the chip could be passed onto human trials, a scandal arose. When initially reporting the findings from the animal trials, Musk and the company insisted that no animals died as a direct result of the neural implant, and the utmost care was taken when handling them [24]. However, based on public documents and testimonials detailing the monkeys’ treatment, the primates in these trials did in fact die and were suffering—undergoing multiple skull-opening surgeries, having them sealed with an unapproved substance called BioGlue, and displaying signs of exhaustion, vomiting, brain hemorrhaging, and a myriad of other concerning health issues [25]. Animals were seen exhibiting stress responses to lights turning on and doors opening, as well as the areas of the cortex where implants were inserted to be “tattered” and have parts taken out [24].
Neuralink was denied approval when it first submitted its proposal to move forward with human trials to the FDA and has even been investigated by the U.S. Departments of Agriculture and Transportation [26]. Despite the publication of the atrocious experimental conditions, the USDA did not reach any conclusive results in its investigation. This only
solicited more criticism, implying that Neuralink was getting a “free pass” because of Musk’s strong status and rank in the tech industry, as well as conflicts of interest among the lawmakers involved in the investigation. When Neuralink reapplied to move forward with human trials, they were given FDA approval in May 2023, leaving many with questions about the ethics of continuing research for neural implants and the pros and cons of moving forward with their development [26]. The concerns present here beg the larger question of whether the development of neural implants for mental illness will suffer the same fate.
Ethical and Technological Concerns
The development of these devices naturally led to discussions surrounding the ethical concerns regarding their implantation. Considering their brain-altering abilities, questions around the scope of these abilities quickly followed suit. Some of the most common questions include, “Is this individual’s thoughts and actions their own?” and “Is this individual's thoughts and actions authentic?” [27]. In the presence of a neural implant, the changes that it can cause in a person’s mood may alter how they recognize their own emotions and express them [27]. If a device detects a change in the brain that correlates with a change in mood or feelings and immediately corrects it through stimulation or administering a drug, can we consider the resulting behavior to be what they genuinely feel? In a way, the implantation of these devices could be seen as preventing raw emotions and actions that were altered by the implant’s activity, and create doubt among others who want to know if the feelings they express are genuine.
These more philosophical considerations directly lead to issues about how to hold people with these devices accountable for their actions if they are being influenced by an implant. These devices have the potential to cause a person to act irrationally as a result of the treatment, as seen in cases where patients being treated with DBS have become increasingly impulsive and aggressive, and display inappropriate sexual behavior [28]. In the eyes of the law, blame for the action wouldn’t fall on the patient because of the changes caused by the device, but they wouldn’t be able to reject accountability completely [28]. If an implant is only integrated with the current networks in one’s brain, it can be argued that the device is simply acting on the patient's original intentions and emotions. If the patient already had these thoughts and intended to act on them, would they be legally responsible for their actions? In the case of voluntarily taking drugs or consuming alcohol, they could [28]. But in the case of involuntary influence such as the usage of prescription drugs and their unintended side effects, there is an argument to be made for why they shouldn’t be held responsible [28].
Other issues with neural implants revolve around the safety of their implementation and maintenance. Despite the compact nature of the actual devices, the process of implanting them into various areas of the brain requires surgery to open the brain. This surgery is highly invasive and comes with several risks, with small missteps by neurosurgeons resulting in potentially disastrous consequences [29]. The risks of surgery and the benefits of its treatment are at odds, with some saying that the treatment is their only hope, and others saying that opening the brain isn’t worth it [29]. When considering safety on a digital level, neural implants present concerns about what kind of data is being collected, who has access to that data, what the data can do, and what happens if the device is hacked. These types of privacy concerns stem from many of the same concerns with other data-collecting technologies. One’s neurological data is private, and without proper security measures in place to restrict who has access to this data and what is allowed to be done with it, this private data can be used without consent by parties with potentially malicious intentions [27, 30]. Implants that have wireless or cloud connections can be vulnerable to cyber attacks and cause catastrophic effects not only for the patients but for those around them [27, 30].
The Future of Neural Implants
Many neural implants currently being developed by companies are still a long way out from becoming widely used alternatives to other drug-based therapies. This is not only because of the technology being used, but also because of hesitant public opinion. Based on research conducted by the Pew Research Center, more than 60% of Americans are at least a little worried about the potential for implanting devices into human brains [31]. While the ethical concerns around what neural implants could change about the human experience will continue to loom over their development, companies like InnerCosmos and their implantable devices hold promise for the future of depression treatment. The development of neural implants for depression may lead to implants for all kinds of mental illnesses. With the goal of finding better and more stable treatment, neural implants could provide a whole new horizon for treatment options. Continuing research into the scope of neural implants pushes us to strive for much needed and long overdue hope and comfort to those experiencing mental illness.
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