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Posttraumatic stress disorder (PTSD) can not only affect service members and their families, but also unit cohesion and operational readiness. PTSD treatment in the U.S. Departments of Defense (DoD) and Veterans Affairs exists on a continuum ranging from outpatient to inpatient, with residential offered as a higher-level, less restrictive option for those who requiring additional care. To understand the impact of residential treatment for active duty service members with PTSD, the Naval Health Research Center (NHRC) collaborated with the OASIS Program to evaluate symptom outcomes over the course of treatment.

What is OASIS?

Overcoming Adversity and Stress Injury Support, or OASIS, is the only residential PTSD treatment program in the DoD, developed and funded by U.S. Navy Medicine to treat Marines and Sailors who served in combat in Iraq and/or Afghanistan. The OASIS Program adapted over time to offer treatment for service members in all branches and for varying trauma types. The program used an integrative approach with evidence-based psychotherapies, medication management, and complementary interventions. The initial program was 10 weeks in duration with approximately 10 patients in each cohort, consisting of 2 phases:

  • Phase 1 (first 2 weeks): Assessment, rapport building, team cohesion, coping skills 
  • Phase 2 (program remainder): Individual and group evidence-based, trauma-focused treatment 


The study examined treatment outcomes for active duty service members in the OASIS Program. The sample included 289 male service members with combat- or deployment-related PTSD admitted to the OASIS Program from 2010 to 2015. Participants completed a range of pre- and postprogram self-report assessments (anxiety, sleep, physical symptoms, resilience, functioning), and weekly PTSD and depression questionnaires. 

PTSD Outcomes

PTSD symptom severity significantly decreased over the course of the program. With each successive week of treatment, symptoms decreased by 0.80 points on the PTSD Checklist. Service members with higher pretreatment PTSD symptoms and those determined unfit for duty demonstrated higher PTSD symptoms on average across treatment. Change in PTSD symptom severity was not predicted by age, any treatment or service-related variable, or treatment discharge status, but by pretreatment PTSD symptom severity.

Depression Outcomes

For depression symptom severity, although service members reported a 0.12-point reduction in Patient Health Questionnaire-8 scores with each consecutive week of treatment, depression symptom severity did not significantly improve over the course of treatment. However, significant reductions were observed for those service members who entered the program with greater depression severity.

Secondary Outcomes

Significant improvements were found in sleep, anxiety, resilience, and functional impairment over the course of treatment. However, when adjusting for age, combat experience, treatment discharge status, and fitness for duty, these improvements were no longer significant.

Trajectories of Change

The study also examined trajectories of both PTSD and depression symptom change. For PTSD symptoms, 23.8% of participants reliably improved, while 8.2% improved, 60.6% remained indeterminate, 4.3% worsened, and 3.2% deteriorated.
For depression symptoms, 9.6% of those who reduced their symptoms reliably improved, 10.3% improved, 67.4% remained indeterminate, 4.3% worsened, and 8.5% deteriorated. 
Results showed a distinct divergence at week 3, when trauma-focused work began, that predicted treatment response. More specifically, at week 3, service members who worsened over time showed increased PTSD and depression severity scores, whereas those who improved over time demonstrated decreased scores. As residential treatment programs are resource-intensive, evaluating trajectories and identifying those most likely to benefit allows for more efficient and effective treatment delivery.


Consistent with meta-analytic findings of residential treatment, PTSD symptoms significantly decreased among service members in the OASIS program. Greater improvements were found for PTSD symptom severity than for depression, with significant decreases in depression shown for those with more severe pretreatment depression. This highlights the need to optimize care provision for service members with severe PTSD and depression, particularly given the high comorbidity between these disorders (Rytwinski et al., 2013; Walter et al., 2018).
Additionally, differing trajectories were found between service members whose symptoms improved over the course of the program and those who did not. Consistent with the literature, a sizeable minority of service members continued to experience significant PTSD and depression following treatment, a finding not entirely unexpected given the greater severity and impairment associated with residential PTSD treatment. In sum, residential treatment programs, like OASIS, provide a higher-level of care that can significantly reduce symptoms of PTSD, while aiming to improve functioning and operational readiness. Future efforts should work to identify those service members most likely to benefit from residential PTSD treatment. 

Reference Article 

Walter, K. H.; Kohen, C. B., McCabe, C. T., Watrous, J. R., & Campbell, J. S. (2021). Overcoming Adversity and Stress Injury Support (OASIS): Evaluation of Residential Treatment Outcomes for U.S. Service Members with PTSD. Journal of Traumatic Stress. https://doi.org/10.1002/jts.22652

Discussion Questions

  • Did depression symptoms respond to residential treatment comparably to PTSD symptoms?  
  • Which response trajectory was most common? Was it the same for PTSD and depression symptoms?
  • What factors might account for why scores diverged among the response trajectories at the outset of trauma-focused work (week 3)?

About the Authors

Kristen H. Walter, Ph.D.
 is a Clinical Research Psychologist and Division Head of the Clinical Research Program at the Naval Health Research Center in San Diego, CA, where she investigates the treatment of posttraumatic stress disorder (PTSD) and conditions that commonly co-occur with PTSD, such as major depressive disorder. She explores both evidence-based psychotherapy and physical activity approaches for treating trauma-related disorders. Twitter: @KristenHWalter1 @NH_RC
Casey B. Kohen, M.A. is currently a doctoral student in Clinical Psychology at the University of Missouri, Columbia. His research focuses on the neurocognitive processes involved in the etiology, maintenance, and abatement of substance use disorders; however, his primary clinical interests focus around the treatment of trauma.
Cameron T. McCabe, Ph.D. is an Applied Social Psychologist and investigator with the Veterans and Active Duty Longitudinal Outcomes Research (VALOR) division at the Naval Health Research Center in San Diego, CA.
Jessica R. Watrous, Ph.D. is a Clinical Health Psychologist, Division Head (contractor) of the Veteran & Active Duty Longitudinal Outcomes Research (VALOR) Division, and Co-PI of the Wounded Warrior Recovery Project (WWRP) at the Naval Health Research Center. Broadly, her clinical and research efforts have focused on the complex relationships between co-occurring mental and physical health problems, and optimizing clinical prevention and intervention protocols for mental and physical health promotion and behavior change.
Commander Justin S. CampbellPh.D., Medical Service Corps, U.S. Navy, is a former director of the OASIS Program and launched the effort to empirically evaluate the effectiveness of the program. He is currently serving as Executive Officer of Field Medical Training Battalion-West.

References Cited

Rytwinski, N. K., Scur, M. D., Feeny, N. C., & Youngstrom, E. A. (2013). The co-occurrence of major depressive disorder among individuals with posttraumatic stress disorder: A meta-analysis. Journal of Traumatic Stress, 26(3), 299–309. https://doi.org/10.1002/jts.21814

Walter, K. H., Levine, J. A., Highfill-McRoy, R. M., Navarro, M., & Thomsen, C. J. (2018). The prevalence of PTSD and psychological comorbidities among U.S. active duty service members, 2006-2013. Journal of Traumatic Stress31(6), 837-844. https://doi.org/10.1002/jts.22337


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