Chris Merkle had no intention of revisiting the traumatic events he experienced in war. After three tours in Iraq and four in Afghanistan, there was plenty to process – but his concern was moving forward, not revisiting the past. "I'm a Marine," he says now, from his home in Los Angeles. "We're taught to do our jobs, to accomplish our mission. We're not going to sit around and talk about our feelings." He'd come here, to Dr. Albert "Skip" Rizzo's lab at the Institute of Creative Technologies at the University of Southern California, after months of working with a therapist with little result. "She was a great therapist," Merkle says, "but she couldn't do anything if I wasn't willing to talk about my experience. And I just wasn't."
At the time, Merkle was struggling with challenges he believed were a result of his present situation, not his past experiences. "It's really hard coming home," he says. "Most of us joined right out of high school. My sense of identity was being part of this group, working for the greater good. When you come home, you lose that." There were practical challenges as well. "I was trained as a machine gunner. There are no machine gunner jobs in the U.S. I didn't want that to be my job, but it was the only thing I had been trained to do." Each vet deals with these challenges in different ways. For Merkle, it was anger. "The slightest thing would send me off. It just got worse and worse."
Merkle reached out to the Department of Veteran's Affairs and was eventually connected with a therapist who suggested he try Virtual Reality-based exposure therapy. Unsurprisingly, Merkle wasn't thrilled about the idea. In VR exposure therapy, a patient enters a virtual re-enactment of a traumatic event. In the case of many vets like Merkle, these events are really multiple traumas, graphic battle scenes imbued with violence, confusion, helplessness, and grief. Simply discussing such a charged scenario is a tall order for most trauma survivors. VR-based exposure therapy goes one step further: the patient is an active participant in the scene, completely immersed in the traumatic incident. Merkle says, "You're going back to the worst day of your life and living it over and over again."
"There's no question," says one doctor. "This is hard medicine for hard problems."
When traumatic event occurs, the brain is overwhelmed with stimuli and everything associated with that trauma (sights, smells, sounds) attaches to the memory like a leech. This happens on a physiological level; the phrase "neurons that fire together, wire together" is an oversimplified but useful way of describing the phenomenon. Under the right conditions, neural firings strengthen the synaptic connections in the brain. It is the neurobiological process that allows us to learn from experience. When it's a traumatic event, however, this process is heightened dramatically; instead of a gradual learning process, the sensory details and the traumatic event itself become almost one and the same, imprinted on an individual's neural circuitry.
These imprints are essential to understanding and treating trauma. The sights, sounds and smells that were present at the time of traumatic incident become embedded as part of the memory. It becomes difficult, if not impossible, to encounter one of the associated sensory details and not recall the entirety of the trauma. It's one of the reasons hypervigilance is such a common symptom of PTSD – a trigger for the traumatic experience could be lurking around any corner, in otherwise innocuous places.
Complicating matters in treating trauma, is that the triggers (or "cues," as Rizzo calls them) are often subconscious. These can prompt a physical or emotional response without the individual realizing why the reaction is occurring. "Stored memories aren't always in the conscious mind," Rizzo says, "a person might only realize something is a cue when that cue appears outside of the traumatic event." I suggest an example: When I was in my early twenties, I needed two emergency surgeries that resulted in a long hospitalization. Six months later, I had an allergy test that required a number of small needle pricks on my arm. Though they didn't hurt in the slightest, I remember sobbing uncontrollably. "Yes!" Rizzo says, "logically, you know you're not back in the hospital. But that cue [being pricked by a needle] tells your brain otherwise."
Exposure therapy, a subset of cognitive behavior therapy, aims to reduce the charge around these cues. Traditionally, exposure therapy ranges from writing a narrative to role-playing the traumatic incident. The premise is the same for any exposure therapy - talking (or writing) through the traumatic event with a trained professional allows a patient to decrease the charge around these cues, revising them in a safe environment with a trained professional.
The key to understanding why exposure therapy works so well in treating PTSD, Rizzo says, is recognizing the instinctive human response to experiencing trauma: avoidance. As with most psychological and physiological responses to stimuli, trauma evolved to protect us. It's the brain's way of making very sure we do everything possible to avoid a similar incident. If the last time you awoke to the smell of smoke, your house was on fire, the smell of smoke in any situation is going to trigger an instinct to flee.
Exposure therapy is designed to, well, expose an individual to those triggering cues in a safe environment. VR-based exposure therapy is an extension of that: completely immersive exposure. That level of exposure is serious business, something Rizzo doesn't take lightly. "There's no question," he says. "This is hard medicine for hard problems."
Chris Merkle didn't feel quite ready for hard medicine. After completing the intake procedures, he was asked to pick a traumatic event to focus on over the course of the 10-week program. He picked a story he thought would be "horrifying to someone on the outside," but one that he didn't think he personally had a lot of trauma around. "I thought I was going to game the game," he says. Merkle picked what he calls his "longest day." "I figured it would give me a lot to talk about without having to go into too many details."
"Avoidance is the biggest challenge to overcome in treating trauma," says Rizzo. It is also the thing that VR therapy is arguably the most effective in minimizing.
Rizzo's team has created 14 virtual worlds from which clinicians can add details specific to the patient's experience. Without VR goggles, the screen looks much like a video game. With VR goggles, a fake gun that reverberates as a real machine gun would when being used, and the brain's ability to fill in gaps based on what is simulated, the experience is utterly immersive.
The event Merkle described, the one Rizzo's team recreated virtually, took place in Iraq in 2003. "We had been rolling through the country, liberating small towns [from the Iraqi opposition] and we reached Nasiriyah," he says. "We were really trying to close the distance to Baghdad. One unit would stay and hold the roadside while another unit rolled through to the next town."
"There is no simulation of killing in VR therapy," Dr. Rizzo says. "We are not desensitizing people to killing."
But there was only one road to get there, and Iraqi forces were doing everything in their power to block it. It was the first time Merkle's unit had faced strong, coordinated resistance. Merkle describes the scene: "I was watching a town under siege, watching Marines dying, it was just... a pathway of death. It was just this horrific scene of all these bodies. I mean, they're humans."
While the bullets were flying, Merkle's unit was hardly moving. "It was this small two-lane highway and there was a massive military unit up ahead," he says. "It was like sitting on the freeway on the back of a dump truck, bumper-to-bumper traffic, without any armor, getting shot at. I'm firing back, seeing lives lost, taking lives, all in this, like, war carpool. It was so surreal."
From the outside, it can sound like what Rizzo has set up is essentially a first-person shooter video game. Rizzo wants to make the distinction very clear. "There is no simulation of killing in VR therapy," he says. "We are not desensitizing people to killing."
Instead, VR therapy addresses both the cognitive part of trauma as well as the behavioral. The patient discusses each cue with the clinician as they encounter it. This is a slow process. "Say someone was driving down a road and what looked like a piece of trash on the side of the road was actually an IED," says Rizzo. "In VR, they might just sit in the humvee on the side of the road for the first few sessions. The clinician will ask, 'what do you see, what do you smell, how does this feel?' The ultimate goal is to allow the patient to see something on the side of the road in real life and not react as though it's a potential bomb."
He continues: "The patient might drive down that road 20 times before the IED goes off. And before it does, we ask the patient, 'is it okay if we activate the IED now?' When the explosion comes, the patient is prepared." The association of that loud noise is taking place where the patient knows they are safe and they can talk about anything that comes up for them in that safe environment. "Ultimately, instead of the cues being paired with the original traumatic event," Rizzo says, "they're paired with what's actually happening now." The patient's cognition around the cues is changing. Talking with a professional as all that information is reprocessed offers the opportunity for behavioral change as well.
This distinction is best illustrated by a new group of patients using VR exposure therapy: sexual assault survivors. A study taking place at Emory University with sexual assault survivors suffering from PTSD is using VR to simulate the non-threatening cues associated with the incident. Being in the location where an assault occurred, be it a bar, an ally, a bedroom, can trigger memories of the trauma itself. VR therapy allows a patient to walk through these charged locations in a safe environment, and talk about the cues as they arise.
In the brain, the details around the trauma are often inextricably intertwined with the traumatic incident itself.
Through VR process, the patient and the clinician are able to talk about every detail leading up to and after the trauma because – as that "fire together, wire together" phrase reminds us – in the brain, the details around the trauma are often inextricably intertwined with the traumatic incident itself. By confronting the traumatic incident in a safe environment, they are creating new memories associated with the cues. In short, it's giving the cues that trigger the memory of the traumatic event something new to wire with: a safe experience.
It also establishes a rapport between clinician and patient, allowing the patient to feel more comfortable discussing the part of the traumatic event that isn't simulated. Critics of VR therapy sometimes claim that the device puts a barrier between the patient and the clinician, but that hasn't been Rizzo's experience. "I've had patients say they think I can better understand what they went through because I'm literally watching them experience it; I'm talking about every detail with them."
There are clinicians who have concerns about the safety of VR, either as therapeutic or recreational tool. Neurophysicist Mayank Mehta at the University of California-Los Angeles Center for Neurophysics has yet-unanswered questions about the long–term effects of VR on the brain. He compared the brain activity of a rat walking down a path in real life vs. a rat walking down an exact replica of the path in VR. "What we found is the effect on the hippocampus is totally different in real life than it is in Virtual Reality. Sixty percent of the neurons in the hippocampus shut down in VR and the ones that don't are totally scrambled." Mehta hopes that VR will be able to be safely used as a therapeutic tool at some point, he stresses the need for longitudinal studies examining the impact of VR on the brain.
The hardest part of taking in the devastation around him in Nasiriyah, Merkle says, was his inability to help those in need. Behind him on the road, he could see Marines taking fire, dying in his wake. "I'm thinking, we've had all of this training for running and fighting and instead of helping, I'm going to die sitting on my ass getting shot at."
By walking through every part of what happened that day, Rizzo and Merkle were able to identify not just the trauma cues but also the deeper roots of Merkle's anger. "The worst thing in the world to feel, especially for a Marine, is helpless," says Merkle. "We're taught to take action." Without VR therapy, however, Merkle may not have ever realized how many layers of trauma he experienced that day in Nasiriyah.
"The mind is powerful. I thought I was giving them a story I didn't need to work on but it turns out that it was something I really, really needed to work on," he says. The process also taught Merkle the importance of facing his vulnerability and of talking about the challenges and traumas he encountered throughout his tours. "If you are a little kid and you burn your hand on a stove and you never see another stove, you're going to be scared of stoves forever," he says. "But if someone walks back to the stove with you, shows you that it's turned off, and provides a comfortable, safe situation for you to interact with the stove, that fear goes away."
VR allowed Merkle to go from avoiding discussing his war-related trauma to working with other vets at the VA. It also gave him a new career path: he's now pursuing a degree in psychology. But there's no easy cure for PTSD, and it's something he still has to work on. "I thought the hard work was out of the way, but that wasn't the case," he says. When he began working with other vets, he found that he was listening to stories that recalled his own trauma and he needed help processing that, so he went back to talk therapy. Before VR, however, he would have avoided anything that made him recall those experiences. Instead, he's fully involved in his work at the VA as well as Team Red White & Blue, and organization that helps vets connect back home. RWB, Merkle says, has helped him address some of the issues that were plaguing him upon his return: how to retain the part of his identity that is a Marine but move on and away from the trauma of war.
Now, he goes on camping trips with other vets, where they can tell their stories and support each other. This community understands him in a way other people can't. "We were up in the woods and it was raining and everyone was sleeping in cabins. But it's hard for me to sleep in that situation, even though I know these guys are my buddies and not the enemy. So I went outside and slept in a hammock. They totally understood. They get it."
"I want other vets to know that you can have a life after war," he says. "That you don't have to run from the things that make you vulnerable; you can embrace them." That doesn't mean the work is over, as Merkle's situation illustrates. But he's found purpose in helping vets navigate the same challenges he experienced. His skills as a machine gunner may not lead to a career, but his experience working through trauma might. "I've always wanted to help people, that's where I find satisfaction," Merkle says, "But it's like those safety announcements on the airplanes – you have to put on your own oxygen mask before you can help someone else with theirs." Thanks to VR-therapy and his own hard work, Merkle says he's less focused on his PTSD. Now, he knows something else is possible. He calls it "Post-Traumatic Growth."