The public health impact of posttraumatic stress disorder (PTSD) treatment is a function of efficacy and reach. Existing evidence-based treatments for PTSD such as exposure therapy are relatively high on the efficacy side of the equation but have very limited reach to those who may benefit from treatment. The evidence supporting the efficacy of exposure therapy to treat PTSD is extensive and robust; exposure is recommended as a first- line intervention by all major clinical practice guidelines (e.g., VA/DoD, 2017). And while there is certainly room to improve the efficacy of exposure therapy (and much ongoing research is currently being conducted in this vein), a most pressing issue is that exposure therapy is woefully underutilized and largely unavailable to most individuals with PTSD (e.g., Borah et al., 2017).  

The prevailing model of mental health care requires highly trained mental health clinicians to deliver treatment directly (e.g., face-to-face) to the client in once-weekly sessions, typically over the course of multiple months. This model of PTSD care is limited in several ways. First, it is not widely available. There is a significant lack of capacity of mental health providers to meet the need for PTSD services and an inequitable geographic distribution of mental health services, with very limited access to care in rural areas. Second, standard PTSD care is not always wanted. Many individuals with PTSD have a desire to resolve their symptoms on their own and to do this work when and where it is convenient for them. Third, standard PTSD care is not always needed. Many individuals with clinically significant symptoms of PTSD may not require a full course of an evidence-based, therapist-delivered treatment in order to achieve recovery. Alternate models of PTSD care delivery are needed to fill the gaps where standard PTSD care is not available, wanted, or needed.  

Using technology to deliver exposure therapy is a promising approach to make this intervention available to more people with PTSD, allow individuals to self-manage their symptoms or participate in care on their own terms, and sufficiently meet the clinical needs of some individuals with PTSD. Technology can be integrated into PTSD care in many ways, such as through mobile apps, web-based programs, and video telemental health, and for different clinical purposes. Some digital interventions may be best suited to engage people in care, others for active treatment, and others for maintenance and relapse prevention. Digital interventions may be wholly self-guided or supported by peer coaches, paraprofessionals, or mental health therapists. These options differ clearly in terms of cost-effectiveness and scalability.     

Exposure therapy for PTSD involves approaching the memory of the worst traumatic event the client has experienced and recounting the memory in detail for a sustained period. Because this can be challenging for clients, it is generally assumed that this technique requires oversight by mental health professionals with advanced training. This begs the question: Can exposure be delivered using technology? Until recently, the safety and efficacy of delivering exposure for PTSD via video telemental health was an open question. Several studies have now demonstrated that this modality of care is safe and effective, with outcomes that are non-inferior to in-person treatment (e.g., Acierno et al., 217). Further, the COVID-19 pandemic necessitated a major boost to the adoption of telehealth, which is now part of standard care. However, while telehealth offers significant advantages in terms of convenience, it requires the same amount of therapist time as in-person therapy, limiting scalability. The safety and effectiveness of other kinds of digital technologies, those that require less therapist time or no therapist time, is less well established. However, research on these types of digital interventions, which has increased considerably in recent years, and in particular since the onset of the pandemic, has yielded promising results. Two examples of this research are shared here for illustration. 
 
Web-PE is a web-based program that mirrors the prolonged exposures (PE) therapy protocol, with 10 sessions comporised of psychoeducation, in vivo exposure, and imaginal exposure and processing. Web-PE sessions are completed independently online and progress is monitored by therapists who provide support and feedback to clients (via phone and email). Web-PE was found to significantly reduce PTSD symptoms in veterans and active-duty military personnel with PTSD in two studies (McLean et al., 2021). One was a randomized trial (n = 40) comparing Web-PE to in-person present-centered therapy (PCT), an effective non-trauma-focused psychotherapy. In this trial, Web-PE was associated with a medium effect (d = 0.58) and Web-PE showed a similar degree of symptom reduction as PCT. The other study was an open trial of Web-PE (n = 34), which found a very large effect for treatment (d = 1.79). Qualitative work (McLean et al., 2021) suggested that Web-PE was helpful, even for those who were initially skeptical of exposure therapy and/or the web-based approach, and that having flexibility to complete sessions at home whenever its most convenient was a perceived advantage of Web-PE over in-person therapy. Qualitative data also suggest that, not surprisingly, completing self-guided sessions required a high degree of self-accountability, motivation, and time-management skills. Effectively engaging individuals with PTSDa disorder characterized by avoidancein digital interventions and sustaining engagement is an important challenge for the field. Human support can impact engagement, but there are many questions about the amount and type of support that remain.  

Renew is an exposure-based self-management mobile app for PTSD that includes two primary exposure components: Process guides users through imaginal exposure (i.e., approaching trauma memories in imagination) using a series of writing prompts. Users may use their phone keyboard or the talk-to-text function, with the goal of describing their worst traumatic event for at least 20 minutes. Approach guides users through in vivo exposure by identifying situations they have been avoiding due to their trauma and building a hierarchy of situations for them to approach. Another novel feature is Support, in which users can invite friends or family to be part of their support team in Renew. Support persons receive a companion version of Renew that provides psychoeducation about PTSD and how to support someone who is using Renew. They also receive notifications when the primary user has completed activities in Renew and are instructed to send encouraging messages through the app’s one-way message system. A recent pilot trial (McLean et al., 2021) found that veterans with clinically significant symptoms of PTSD who used Renew reported reductions in PTSD symptoms over a six-week period, whereas veterans in a waitlist condition did not, until they began using Renew, at which point they too experienced significant reductions in PTSD symptoms. Although the effect of Renew relative to waitlist was small, these findings, along with qualitative data that support the helpfulness of the app, suggest that Renew may be an effective self-management tool to reduce PTSD symptoms. Preliminary data also suggest that use of the Support feature was associated with engagement, and that the degree of engagement with the exposure components of Renew was associated with PTSD symptom change.  

Taken together, the results of these findings suggest that exposure-based digital interventions for PTSD may be acceptable and efficacious. Participants in both studies valued the convenience of the digital approach. Digital interventions can be self-paced, potentially allowing for more rapid symptom reduction if sessions or therapeutic exercises are massed in time. As noted, however, relying on clients to independently engage and self-pace may be ineffective in the absence of human support to promote adherence through accountability (e.g., Mohr et al., 2011). Interestingly, a subset also preferred doing imaginal exposure independently, because this allowed them to conserve the emotional resources that would otherwise go towards consideration of the therapists’ reactions to hearing their trauma. This may represent another advantage to delivering exposure through digital approaches for some individuals. 

Relying on therapists to deliver evidence-based treatments for PTSD, even with the advancements in video telemental health, will not adequately meet the need for PTSD care. There will always be people with PTSD who do not receive this type of care because they cannot access it, do not want it, or do not need it. More scalable evidence-based interventions for PTSD like Web-PE and Renew have a higher potential reach and cost-effectiveness because therapist time is significantly lower. Given the anticipated rate of technology adoption globally, there is real potential to reduce the burden of PTSD through digital interventions. Even self-management tools like Renew or the excellent, publicly available mobile app PTSD Coach, which may have a more modest impact on symptoms relative to higher-touch interventions, have important public health implications given their scalability. The finding that including supportive peers may improve app engagement also has important public health implications, since this is a no- cost means of incorporating human support.  
Increasingly, society expects to receive goods and services on demand, including behavioral health care. In response, digital interventions have proliferated, but most do not include evidence-based components and have not been empirically evaluated. When translating psychological approaches to digital formats, there may be an inclination to omit exposure given common misconceptions about its tolerability. However, as the work referenced here clearly illustrates, powerful, well-established therapeutic approaches like exposure should be considered when designing digital interventions for PTSD to maximize public health impact. 

About the Author 

Dr. Carmen McLean is a licensed clinical psychologist and researcher with the Dissemination and Training Division of the National Center for PTSD at the Palo Alto VA Health Care System and a clinical associate professor (affiliate) at the Department of Psychiatry and Behavioral Sciences at Stanford University. Her research examines ways to increase the reach of exposure therapy for PTSD by addressing implementation barriers and testing eHealth interventions.
 
Keywords: PTSD treatment, exposure therapy, digital interventions, mobile apps  

Resources Web-PE and Renew are not currently publicly available. Interested trauma practitioners are welcome to contact Dr. McLean with questions about the program at carmen.mclean4@va.gov.  

References 

Acierno, R., Knapp, R., Tuerk, P., Gilmore, A. K., Lejuez, C., Ruggiero, K., ... & Foa, E. B. (2017). A non-inferiority trial of prolonged exposure for posttraumatic stress disorder: in person versus home-based telehealth. Behaviour Research and Therapy, 89, 57-65. 

Borah, E. V., Holder, N., Chen, K. (2017). Providers' Use of Evidence-Based Treatments for Posttraumatic Stress Disorder: The Influence of Training, Attitudes, and Barriers in Military and Private Treatment Settings. Best Practices in Mental Health, 13(1), 34-46. 

McLean, C. P., Davis, A., & Miller, M. (2021, November). Pilot evaluation of Renew: an exposure-based self-management app for PTS. [Symposium presentation]. The 37th Annual Meeting of the International Society for Traumatic Stress Studies, Virtual Conference.  

McLean, C. P., Foa, E. B., Dondanville, K. A., Haddock, C. K., Miller, M. L., Rauch, S. A., ... & Peterson, A. L. (2021). The effects of web-prolonged exposure among military personnel and veterans with posttraumatic stress disorder. Psychological Trauma: Theory, Research, Practice, and Policy, 13(6), 621. 

McLean, C. P., Miller, M. L., Dondanville, K. A., Rauch, S. A., Yarvis, J. S., Wright, E. C., ... & Foa, E. B. (2022). Perceptions and experiences of web-prolonged exposure for posttraumatic stress disorder: A mixed-methods study. Psychological Trauma: Theory, Research, Practice, and Policy. 

Mohr, D., Cuijpers, P., & Lehman, K. (2011). Supportive accountability: A model for providing human support to enhance adherence to eHealth interventions. Journal of medical Internet research, 13(1), e30. 

VA/DoD, The Department of Veterans Affairs and the Department of Defense clinical practice guideline for the management of posttraumatic stress disorder and acute stress disorder; 2017.