Renew is a self-management app for symptoms of PTSD. Renew is unique from PTSD Coach in that it was designed to treat PTSD symptoms, whereas PTSD Coach was designed to help people manage and reduce acute experiences of distress. Renew was developed by Vertical Inc. and is owned by the Department of Veterans Affairs. An initial build of the app was revised using feedback from volunteers who had experienced a traumatic event during a small feasibility and usability study of Renew [32].

The app includes 2 primary exposure components, namely, process and approach. Both include a rationale, detailed instructions, and examples, with prompts for users to provide a 0-100 subjective unit of distress (using the Subjective Units of Distress Scale [SUDS]) rating before and after each activity. Process guides users through imaginal exposure (ie, approaching trauma memories through imagination) using a series of writing prompts. In this activity, users describe their worst traumatic event for at least 20 minutes, using either their phone keyboard or the talk-to-text function. Approach guides users through in vivo exposure by identifying real-life situations they have been avoiding due to their trauma and building a hierarchy of situations for them to approach.

A learn section includes psychoeducation about common reactions to trauma, the development of PTSD symptoms, the role of avoidance in maintaining symptoms, and the science behind exposure therapy techniques. The self-care section allows users to identify and schedule self-care activities that promote relaxation, physical activity, and social engagement. Support allows users to invite trusted friends or family members to be part of their support team in Renew. Support persons are invited to download “Renew Support” (available on Apple and Android smartphones), which provides psychoeducation about PTSD symptoms and information on how to support someone who is working on managing PTSD symptoms. Support team members receive notifications when the primary user earns points or achieves a new level and are instructed to send an encouraging message through the app’s 1-way message system. Motivate allows users to personalize the app by selecting quotes, videos, and images that motivate them to work on managing their PTSD symptoms. Users may add their own or select from Renew’s built-in options. In progress, users can complete a 5-item “symptom tracker” assessing coping self-efficacy, depression, and PTSD symptoms. Users can view the results of these assessments, as well as the SUDS data from process and approach, over time in a graph view (Figures 1-6). Renew prompts users to complete assessments every 2 weeks.

In addition to the main sections, Renew includes elements of gamification: users earn points for completing activities in the app and can level up to unlock new features and activities. Crisis resources are also listed in the app. Users can turn on daily notifications and receive reminders to use Renew.

Participants were recruited via online advertisements from across the United States (Figure 7 and Multimedia Appendix 1). Inclusion criteria were age 18 years or older, veteran status, exposure to a criterion A trauma, a PTSD symptom severity score of 31 or greater [33] on the PTSD Checklist for the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) [34], and access to an Android smartphone.

Potential participants completed an online screening assessing study enrollment criteria. Eligible participants were then emailed the informed consent information sheet and met with a study RA by phone to complete the informed consent process (see Multimedia Appendix 2). After completing a baseline assessment, consented participants were randomized by the study RA and informed of their condition assignment over the phone, at which point participants and researchers were unblinded to study condition. Randomization was done by a study RA using an online random block generator allocating participants to the 3 groups using a 1:1:1 ratio. Participants assigned to either of the 2 active treatment conditions were guided through downloading Renew and given a special code to allow them access to Renew’s content during a 30-minute in-depth orientation to the app delivered by a study RA.

After the 6-week app-use phase, participants completed a postuse online survey and a brief telephone interview. All surveys were sent to the participants’ emails via REDCap, a secure online data collection tool that enables users to design and administer questionnaires. Interviews were audio-recorded and transcribed by study RAs. Participants in the active use conditions completed a follow-up assessment online 6 weeks after the postuse assessment (ie, week 12). Participants in the delayed use condition only completed pre- and postuse surveys. Participants were compensated with an online gift card in the amount of US $100 after study completion. Study data were collected from July 18, 2020, to February 3, 2021.

Our first hypothesis was that veterans in either treatment condition would show greater reductions in PTSD symptoms relative to delayed use. We also hypothesized that veterans who were assigned a support team member would engage with Renew more and show greater reductions in PTSD symptoms than those who were not assigned a support team member. In addition, we explored the relationship between indices of support and indices of app engagement.

The primary hypothesis was tested using the MIXED procedure [39] in SAS 9.4 (SAS Institute) [40] to fit a mixed analysis of variance (ANOVA) model. Restricted maximum likelihood estimation was used to conduct the analysis following the intention-to-treat principle and allow for missing data. For the equally spaced time points, which included the 6 weeks from baseline to posttreatment and the 6 weeks from posttreatment to follow-up, the model assumed an autoregressive error covariance structure. The model included time and treatment group as factors with the interaction term testing group differences in PCL-5 change or slope, which was the primary outcome of interest.

For analyses of indices of support, the variables of interest were characterized by skew distributions where nonparametric tests are more appropriate: for the secondary hypothesis comparing indices of support between the 2 active use conditions, we used the Mann-Whitney-Wilcoxon test and area under the receiver operating characteristic curve effect size [41]. For the exploratory analysis of associations with indices of support, we used the Spearman’s rank correlation coefficient.

This study was approved by the Stanford Institutional Review Board (IRB-52829).

Our results provide support for the preliminary efficacy of Renew, with a small effect favoring app use compared with delayed use. The between-group difference was not significant, although veterans who used Renew reported reductions in PTSD symptoms, whereas veterans in the delayed use condition did not, until they began using Renew. PTSD symptom reduction during the active use phase was approximately 6 points on the PCL-5 for those in the active use condition and 10 points for those in the delayed use condition, which is comparable to findings from a study of PTSD Coach in a community sample of trauma survivors over a 1-month period (7 points) [11]. These findings suggest that Renew may represent another effective self-management tool to reduce PTSD symptoms.

The 6-week use period was short relative to other studies and may have underestimated the effect of Renew. The pattern of PTSD symptom change indicates some continued improvement during the follow-up period, which is consistent with research on PTSD Coach showing that symptoms declined over a 3-month use period and, to a lesser degree, a subsequent 3-month follow-up [12]. Thus, it seems warranted to examine the impact of Renew over a longer use period in future studies.

Contrary to hypothesis, we did not see greater app engagement or PTSD reduction among those in the support condition, who were assigned a study staff person as one of their support team members relative to those in the no support condition. The support condition may not have been impactful because the study staff person is not someone the veteran knows personally.

Consistent with this interpretation, the results of the exploratory analyses suggested that adding friends or family as support team members did promote engagement with Renew. The number of support persons added (ie, beyond the study staff person as required by study condition) was associated with greater overall time spent in Renew, greater time spent in exposure, and achieving a greater number of points. Potential reasons for this association could be that adding a support team member, which informs that person that the user is working to manage symptoms of posttraumatic stress, could promote self-accountability or could open the door to more direct forms of social support (eg, supportive conversations between the participants and their support person). The effect could also be related to receiving encouraging messages from the peer support person(s) through Renew. This finding has important public health implications because it suggests that incorporating peers may represent an effective approach to improve app engagement at no cost. However, it is important to keep in mind that we do not know the direction of this relationship. Participants who engaged more with Renew could have been more inclined to add support persons, or those who added more support persons could have felt more encouraged to use Renew. We did not find that the number of support messages received was related to app use, but we were not able to isolate messages from peer support team members from study staff members.

Veterans in this study were instructed to use the app as much as they wanted for 6 weeks and were oriented to and encouraged to try all components of Renew. Although those in the support condition received messages in response to their use of Renew, there was no synchronous coaching provided (eg, coaching phone calls). This allowed us to approximate what the effect of Renew may be in routine use, with no additional resources provided. However, it is possible that scaffolding to support app engagement would have resulted in greater clinical benefit. Future studies could explore the impact of Renew with coaching or as an adjunct to more traditional care (eg, including a therapist as a support team member). The Efficiency Model of Support [43] could be a relevant protocol to use in future studies of Renew to further evaluate the effectiveness of the support function.

Several study limitations should be considered. First, participants were veterans and therefore the findings may not generalize to other populations, including civilians. Second, most of the data collection occurred during the first wave of the COVID-19 pandemic in the United States, when movement restrictions were high and vaccines were unavailable. It is unclear how much COVID-19–related stress impacted PTSD symptoms, app engagement, or outcomes in our study sample. Other research with veterans enrolled in PTSD psychotherapy suggests that the COVID-19 pandemic worsened PTSD symptoms [44] and negatively impacted engagement with treatment [45]. It may be that COVID-19–related stressors had a similarly negative impact on PTSD symptoms and engagement with Renew. We are currently examining data on COVID-19 stressors in this sample in an effort to better understand the impact of the pandemic on the veteran’s experience using Renew. Finally, we were not able to disaggregate the number of support message from study staff and peers, limiting our ability to understand how this feature was related to engagement.

Given the preliminary efficacy of Renew, future research evaluating the app is warranted and several possible directions can be considered. First, based on the pattern of change during the follow-up period and findings from PTSD Coach [11], we recommend that Renew be tested in a longer use period than 6 weeks. This would allow researchers to explore an optimal “dosage” of Renew. Second, in light of the exploratory findings on the support feature, future work may also examine ways to encourage users to develop a personal support team. Third, research examining engagement with different components of Renew may be useful to determine whether the use of particular features (eg, exposure components) is most closely associated with symptom reduction. Finally, future work may consider testing Renew as a supplement to psychotherapy or as part of a stepped care model. For example, Renew may be useful for individuals waiting to initiate psychotherapy or who have completed psychotherapy and might benefit from Renew as a tool to help them maintain their therapy gains.

Study limitations notwithstanding, our findings indicate that Renew holds promise as a self-management tool for PTSD symptoms. The effect of Renew relative to the delayed use condition was small over 6 weeks of use. However, given the scalability and cost-effectiveness of mobile mental health apps, even tools with a small effect have potential to help address the unmet need for mental health care among individuals struggling with PTSD symptoms. While not a replacement for traditional treatment, self-management tools such as Renew may represent a sufficient level of care for a proportion of veterans struggling with PTSD symptoms and may also help veterans seek a higher level of care as needed.