Applying Mixed Methods to Identify Links Between PTSD Symptoms, Cannabis Use, and Functional Behaviors With Personalized Feedback Intervention Development

Posttraumatic stress disorder (PTSD) and cannabis use are highly prevalent among Veterans, frequently co-occurring in ways that compound impairment and reduce quality of life. Many Veterans use cannabis to manage PTSD symptoms despite limited empirical support. Although the 2023 VA/DoD Clinical Practice Guidelines advise against cannabis for PTSD, a significant proportion of Veterans continue to use it. Both PTSD and cannabis use independently impair psychosocial functioning, and their combined day-to-day impact remains poorly understood. This CDA-2 focuses on developing and refining a motivational interviewing (MI)-based, personalized feedback approach that uses real-time data to help Veterans better understand how cannabis use relates to PTSD symptoms and daily functioning, with the goal of supporting healthier coping and functional recovery. This project uses ecological momentary assessment (EMA) and wearable activity tracking to support the development and refinement of an MI-based personalized feedback session for Veterans with PTSD who use cannabis. This personalized, data-driven approach yields foundational tools for future VA implementation.

Sixty Veterans with PTSD and regular cannabis use will complete a 14-day EMA protocol (3 random prompts, 2 daily diaries per day) and Fitbit tracking. The study will use a phased design. Phase 1 (n=20) informs PFS development. Phase 2 (n=10) pilots the 1st iteration PFS. Using qualitative feedback from Phase 2 participants and experts, the 2nd iteration PFS will be developed and piloted with a single-arm design in Phase 3 (n=30). Phase 3 tests the 2nd iteration PFS with 1- and 3-month follow-up assessments. Similarly, qualitative feedback will be gathered from Phase 3 participants to further refine the PFS for use in a future VA Merit Award randomized clinical trial. Outcomes include real-time reports of PTSD symptoms, cannabis use episodes, and functioning domains, analyzed using multilevel and network models. This CDA-2 will generate the empirical and methodological foundation needed to support a future VA Merit Award focused on fully testing an MI-based personalized feedback session. The long-term goal is to build the foundation for scalable self-management tools that support functioning and recovery among Veterans with co-occurring PTSD and cannabis use within the VA healthcare system.

Inclusion criteria

• U.S. Military Veterans
• DSM-5 PTSD diagnosis verified by the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5)
• Cannabis use at least once per week over the past 3 months
• If on psychotropic medication or in psychotherapy (excluding trauma-focused PTSD therapy; see exclusion criteria), regimen must be stable for =1 month
• English-speaking and reading
• Willing and able to use a smartphone and wearable device for 2 weeks

Exclusion criteria

• Severe substance use disorder (excluding cannabis), as acute withdrawal or other drug effects could confound data; mild/moderate non-cannabis disorders permitted with monitoring
• Lifetime diagnosis of schizophrenia or other primary psychotic disorder due to potential confounding of EMA responses
• Severe depression or high suicide risk; such Veterans will be referred for treatment and may be re-evaluated once stabilized
• Cognitive or neurodegenerative disorder impairing ability to use EMA tools (e.g., moderate/severe TBI or dementia)
• Veterans currently engaged in evidence-based trauma-focused therapy (e.g., CPT, PE, EMDR), will be excluded to isolate naturalistic symptom variability, as therapy can substantially impact PTSD symptoms; these individuals will be invited to re-contact the study post-treatment for consideration
• Lack of smartphone ownership