As many as 20 percent of war veterans return from combat in Afghanistan and Iraq with post-traumatic stress disorder (PTSD) or major depression, according to a 2008 report from the RAND Corporation. Many experience constant nightmares and flashbacks and many can’t live normal lives. For significant number of veterans, available medications do not seem to help. In 2010, at least 22 veterans committed suicide each day, according to the Department of Veterans Affairs. In her book, Demon Camp, the author Jen Percy describes damaged veterans who have even resorted to exorcism to alleviate their PTSD symptoms.

As part of President Obama’s BRAIN Initiative, the federal Defense Advanced Research Projects Agency (DARPA) plans to spend more than $70 million over five years to develop novel devices that would address neurological disorders such as PTSD. DARPA is particularly interested in a technology called Deep Brain Stimulation (DBS). DBS involves inserting a thin electrode through a small opening in the skull into a specific area in the brain; the electrode is then connected by an insulated wire to a battery pack underneath the skin; the battery pack then sends electrical pulses via the wire to the brain.

About 100,000 people around the world today have a DBS implant to ameliorate the effects of Parkinson’s disease, epilepsy and major depression. There is evidence that DBS can also help with PTSD. Functional neuroimaging studies indicate that amygdala hyperactivity is responsible for the symptoms of PTSD and that DBS can functionally reduce the activity of the amygdala. In animal PTSD models, DBS has been found to be more effective than current treatment using selective serotonin reuptake inhibitors.

DARPA wants to develop the next-generation, deep brain stimulators (call them DBS+) that do not require user input and that can a) read and monitor the brain’s activities in real-time using neural recording, and b) intervene in these activities in an automatic way through electrical stimulation.

DARPA’s officially stated goal is to treat soldiers who have PTSD and other related neurological disorders. However, once DBS+ is developed, theoretically it could also be used to fortify soldiers’ minds. For example, DBS+ could be used to pre-empt PTSD. Suppose that a soldier has just experienced a potentially traumatic event. DBS+ could be used to detect and categorize the emotional reaction in the amygdala. Like tsunami warnings, there could be different categories. If DBS+ detected a Category 4 reaction, it would automatically reduce the activity in the amygdala to a certain degree. If DBS+ detected a Category 5 reaction, it would slow the amygdala to a halt.

When the emotional strength of one’s memory is reduced, the memory tends not to get consolidated as strongly into long-term memory. Indeed, in both military and non-military settings, the beta-blocker propranolol has been used to dampen the emotional strength of one’s memory as a means of reducing potential trauma. By monitoring the brain in real time and intervening when necessary, DBS+ has the potential to be more precise and efficient while having fewer side effects.

Once DBS+ is developed, it could also be used to modulate other emotions. Suppose that a soldier is about to enter combat. DBS+ could be used to reduce/remove fear and/or increase courage by increasing adrenaline in the soldier, much like psychotropic drugs such as amphetamine that some soldiers now use. In animal models, DBS reduces fear expressions when applied to the dorsal area of the ventral striatum.

The development of DBS+ will raise familiar but important questions that pertain to the development of all new biotechnologies, including safety and risks. Also, DBS+ is likely to raise some of the same ethical issues that current DBS faces, such as those of authenticity and alienation. For instance, after using DBS, some patients have said things like “During those years of illness, I was asleep. But now I’m going to take my life back.” Others have said things like “I don’t recognize myself anymore.”

The benefits of DBS+ will therefore need to be weighed against its damaging potential to distort or disturb our sense of self. Moreover, DBS has been known to have unintended negative and positive effects. In some patients with Parkinson’s disease, DBS has taken away their tremors but also their passion to lead an active life. In other patients with Parkinson’s disease, DBS has made these patients feel ‘well’ and ‘happy’ even though DBS has not reduced their symptoms. These issues will make DBS+ a future technology that is likely to generate serious public debates.

But even if DBS+ is safe, some people will rightly be concerned that soldiers may be forced to use this kind of brain modification. Suppose soldiers were only equipped with DBS+ on condition of their informed consent after being properly informed of the various risks and benefits. Would all the ethical concerns have been addressed? Perhaps not.

Even if there were informed consent, there could be subtler forms of coercion. The military command structure is hierarchical. This could make “consent” less than fully voluntary. If a commanding officer were to strongly urge the use of DBS+, would this not influence the choices of subordinate officers? Also, there may be subtle or not-so-subtle forms of peer pressure. A soldier may agree to use DBS+ because the soldier does not want to let fellow soldiers down. Moreover, if a soldier does not use DBS+, the soldier may be at a competitive disadvantage. Soldiers with DBS+ may be more reliable under pressure than soldiers without DBS+ and may therefore be more likely to be called upon and shouldered with responsibility.

Could we just ban the use of DBS+ in the military, just as we ban the use of steroids in sports? It is not clear that this is a viable option. Soldiers are already enhanced in other ways. They have access to night vision goggles, Apache helicopters and drugs such as Modafinil to improve alertness and Ritalin to enhance attention. Also, banning doping in sports is usually done for considerations of fairness, but these reasons are unlikely to sway any soldier/state institutions. Would any soldier voluntarily give up advanced military weaponry just to level the playing field? Moreover, if one’s enemies have acquired the technology and are using it, this will undoubtedly provide a strong incentive for its use.

Others might worry that using DBS+ would lead to conscienceless soldiers who would kill indiscriminately in ways that are out of reasonable proportion. This is a serious and important concern. Interestingly, this may be a “technical” problem.

Brain implants that reduce or eliminate our sense of morality are morally undesirable and are not really enhancements as such. Efforts should therefore be made to ensure that the kind of brain implants we develop do not have these unwanted side effects. In the short term, the brain implants we develop may well be imperfect in just such a way. If so, this would be a good reason to ban such devices in the short term. The interesting theoretical issue is what happens when we have perfected the technology and have brain implants that would enable a soldier to kill at the right time, for the right reasons, and in a proportionate manner? Would we still have ethical problems with soldiers using such a technology?