Obesity and post-traumatic stress disorder (PTSD) are common among Veterans. PTSD increases risk for obesity, impacting functioning, health, quality of life, and premature mortality. Use of proven treatments for PTSD and obesity in VA is low. Furthermore, Veterans with PTSD lose less weight than those without PTSD in VA's national weight management program. Based on pilot work, an integrated treatment that combines PTSD and weight management care-using behavioral and pharmacologic approaches-may improve weight and PTSD. Whether it improves these outcomes more than standard VA care is unknown, which is the focus of this study. The study also seeks to understand factors that would interfere with and facilitate implementing the program in VA if it is effective. This Veteran-centered program may be a more efficient and effective treatment for Veterans with PTSD and obesity, addressing both physical and mental health.

Background: Obesity and post-traumatic stress disorder (PTSD) are highly prevalent among Veterans. PTSD increases risk for obesity and related conditions, in part due to PTSD symptoms interfering with physical activity and healthy diet. VA offers effective evidence-based behavioral and pharmacologic weight management and PTSD treatments, but utilization is low. Veterans with PTSD also lose less weight than those without mental health conditions in VA's MOVE! behavioral weight management program. In response, the investigators developed HARPP-an integrated weight and PTSD treatment-to promote improved access, efficiency, and outcomes. HARPP is a manualized 16-session individually-delivered treatment that combines VA's MOVE! behavioral weight management program and cognitive processing therapy (CPT), enhanced to address obesity-PTSD intersections, and medication review and management. The latter focuses on identifying obesogenic medications that could be changed and eligibility for anti-obesity medications (AOM) through chart review, ~2-3 virtual visits with an obesity specialist, and close coordination with Veterans' care teams. In a pilot of HARPP among 7 Veterans, participants reported high satisfaction, and experienced substantial weight loss and PTSD symptom reduction. HARPP effectiveness must be tested in a randomized controlled trial (RCT).

Significance/Impact: The study aligns with VA and HSR priorities, given its focus on meaningful Veteran engagement to develop and test a novel, Veteran-centered, whole health intervention focused on improving access and outcomes for Veterans with PTSD, a priority VA population. This study's identification of implementation determinants would place effectiveness findings in context and facilitate translation to clinical care if HARPP is effective. This study will also yield insights about how weight management and PTSD care can be enhanced broadly. For example, the medication protocol and templates could be of use broadly in VA.

Innovation: HARPP is the first integrated treatment designed to address obesity and PTSD simultaneously.

Specific Aims: The investigators will randomize 182 Veterans with PTSD and obesity to control (standard CPT, referral to standard MOVE!, and one non-visit consult medication review) or intervention (HARPP, described above) to address the following aims: 1) Test whether intervention participants have greater absolute weight loss in pounds and PTSD symptom reduction relative to controls at 6 (secondary outcomes) and 12 months (co-primary outcomes); 2) Assess whether taking AOM mediates the relationship between HARPP and 12-month weight loss; and 3) Assess implementation determinants (acceptability, feasibility, fidelity, and cost).

Methodology: The investigators propose to conduct a hybrid type 1 RCT among Veterans with PTSD and obesity to test the primary hypothesis that HARPP participants will have greater 12-month absolute weight loss in pounds and PTSD symptom reduction relative to Veterans enrolled in the control group. The Veteran Engagement Group will consult throughout the study, ensuring Veteran-centeredness.

Next Steps/Implementation: If trial findings suggest HARPP is effective, the study team will partner with Veterans and operational leaders to develop a HARPP implementation package that will be tested in a multi-site hybrid type 2 trial, findings of which will inform broad VA implementation. Implementation activities would be coordinated with existing local, VISN, and national operational partners. If HARPP is not effective, Aims 2 and 3 will help understand how Veterans with PTSD and obesity could be better supported in the future.

Inclusion Criteria:

1. Veteran adult
2. Current PTSD Diagnosis per the revised Clinician-Administered PTSD Scale for DSM-5 (CAPS-5-R)
3. Obesity: BMI of 30 kg/m2
4. Enrolled in VA Puget Sound primary care to ensure safety and facilitate HARPP's medication component
5. Willing to do intervention or control and assessments

Exclusion Criteria:

1. Not fluent in English, severe hearing loss, no phone access
2. Recent MOVE! or CPT participation (2 visits in past 2 months)
3. Had bariatric surgery in past 6 months or plans to receive it in next 12 months
4. At least 1 fill of AOM in the past 90 days
5. Current pregnancy
6. Any history of a bulimia diagnosis and/or meets criteria for bulimia
7. Cannot participate due to a) acute substance use, mental health, or medical exacerbation or b) at least moderate neurologic conditions, e.g., dementia
8. Current weight 600lbs or greater to accommodate study scale restrictions
9. Unable to complete a standing weight and height measurement to accommodate study scale restrictions

Staff will not be able to predict treatment assignment at the point of randomization. Assessors, and biostatisticians will be masked until after 12-month data collection.