Scientists at The University of Texas at Dallas and Baylor University Medical Center have demonstrated unprecedented success in treating treatment-resistant PTSD, achieving complete loss of diagnosis in all nine participants of a Phase 1 clinical trial. The groundbreaking study, published in Brain Stimulation, combined traditional prolonged exposure therapy with vagus nerve stimulation (VNS), resulting in symptom-free patients up to six months after treatment completion.
Remarkable Clinical Outcomes
The trial achieved what Dr. Michael Kilgard, the Margaret Fonde Jonsson Professor of neuroscience in the School of Behavioral and Brain Sciences, described as extraordinary results. "In a trial like this, some subjects usually do get better, but rarely do they lose their PTSD diagnosis. Typically, the majority will have this diagnosis for the rest of their lives," Kilgard explained. "In this case, we had 100% loss of diagnosis. It's very promising."
This outcome stands in stark contrast to current gold-standard treatments, which according to Dr. Mark Powers, lead author and research center director of the Trauma Research Center at BSWRI, achieve "about an 85% response rate, with 40% no longer having their diagnosis, and a 20% dropout rate."
Treatment Protocol and Technology
The study paired prolonged exposure therapy—a form of cognitive behavioral therapy where patients gradually confront trauma-related thoughts and memories in a safe environment—with concurrent vagus nerve stimulation. Participants received short bursts of stimulation via a small device implanted in their neck during a standard 12-session therapy course.
The VNS device represents a significant technological advancement. Dr. Robert Rennaker, professor of neuroscience and the Texas Instruments Distinguished Chair in Bioengineering, noted that "the device is about 50 times smaller than our version from just three years ago" and is now approximately the size of a dime. The wireless device has demonstrated exceptional safety, with 49 people in the Dallas area having "a combined 100 years of experience with it implanted" without issues.
Scientific Foundation and Mechanism
The approach builds on 13 years of research by the Texas Biomedical Device Center (TxBDC), which has previously demonstrated that VNS paired with rehabilitation can accelerate neuroplasticity—the brain's ability to rewire itself. This work has already resulted in FDA approval for treating impaired upper-limb movement in stroke patients.
"The common theme in our VNS work is that we're taking therapies that show potential, like prolonged exposure therapy for PTSD, and making them work better," Kilgard said.
Clinical Significance and Patient Population
The research addresses a critical unmet medical need. The National Center for PTSD estimates that 5% of adults in the U.S. have post-traumatic stress disorder in any given year, with women twice as likely to develop PTSD at some point in their lives. Many patients fail to respond to existing therapies or experience intolerable side effects, leaving them without viable treatment options.
Kilgard emphasized that PTSD extends beyond military veterans: "When you hear PTSD, you may picture a combat zone, but it's much more prevalent than that. It can stem from any event that inspires fear of death or bodily injury, or death of a loved one."
Future Development and Regulatory Path
The research team is advancing toward FDA approval with a double-blind, placebo-controlled Phase 2 pilot study currently ongoing in Dallas and Austin. "We hope that it will represent another step toward FDA approval of a treatment that doesn't exist now, and it would be invented, tested and delivered by UT Dallas, as was the case for upper-limb recovery after stroke," Kilgard stated.
Dr. Powers highlighted the transformative potential of this approach: "VNS has changed my work dramatically. Soon we could have the option of VNS for people who don't get better with cognitive behavioral therapy alone."
The study represents the largest clinical trial to date using an implanted device for PTSD treatment and was funded by a grant from the Defense Advanced Research Projects Agency. The collaborative effort between UT Dallas and Baylor Scott & White Research Institute demonstrates what Powers described as "multidisciplinary synergy" essential for advancing complex medical technologies from laboratory discovery to clinical application.
