Deployment-related traumatic stressors and subclinical depression among peacekeeping veterans

Alex Siira; Toni Survonen; Petteri Simola; Sami Määttä

doi:10.2478/jms-2026-0003

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Deployment-related traumatic stressors and subclinical depression among peacekeeping veterans

Journal of Military Studies

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By: Alex Siira, Toni Survonen, Petteri Simola and Sami Määttä

Open Access

|Oct 2026

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Abstract

Subclinical depression among peacekeeping veterans remains understudied despite its prevalence and potential to progress to major depression. This study examined associations between deployment-related traumatic stressors and subclinical depressive symptoms in 2,258 Finnish peacekeeping veterans. Subclinical depression was measured using the Depression Scale (DEPS) and traumatic stressor exposure via a 16-item questionnaire. Frequent traumatic stressor exposure was associated with an increased risk of subclinical depression, with 5 out of 16 stressors showing significant associations. The strongest predictor was feeling powerless to help sufficiently within one’s role as peacekeeper, suggesting moral injury significantly contributes to the development of subclinical depression. These results highlight the importance of developing post-deployment screening to detect non-danger-based stressors and subclinical conditions that carry the risk of progressing into severe mental health disorders.

References

Act on Military Crisis Management. (2006). (Finland), 211/2006. Available at: https://www.finlex.fi/fi/laki/ajantasa/2006/20060211 [accessed 5 December, 2025].
Search in Google Scholar Back to article
American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders, 5th edn. American Psychiatric Association, Washington, DC.
Search in Google Scholar Back to article
Anyan, F., Nordstrand, A. E., Hjemdal, O., Rønning, L., Huffman, A. H., & Noll, L. K., et al. (2024). Development and validation of a brief warzone stressor exposure index. Assessment, 32(8), pp. 1235–1249. doi: 10.1177/10731911241298083
Open DOI Search in Google Scholar Back to article
Asmundson, G. J. G., Stein, M. B., & Mccreary, D. R. (2002). Posttraumatic stress disorder symptoms influence health status of deployed peacekeepers and nondeployed military personnel. The Journal of Nervous and Mental Disease, 190(12), pp. 807–815. doi: 10.1097/00005053-200212000-00002
Open DOI Search in Google Scholar Back to article
Bartone, P. T., Adler, A. B., & Vaitkus, M. A. (1998). Dimensions of psychological stress in peacekeeping operations. Military Medicine, 163(9), pp. 587–593. doi: 10.1093/milmed/163.9.587
Open DOI Search in Google Scholar Back to article
Ben-Zeev, D., Corrigan, P. W., Britt, T. W., & Langford, L. (2012). Stigma of mental illness and service use in the military. Journal of Mental Health, 21(3), pp. 264–273. doi: 10.3109/09638237.2011.621468
Open DOI Search in Google Scholar Back to article
Borsboom, D. (2017). A network theory of mental disorders. World Psychiatry, 16(1), pp. 5–13. doi: 10.1002/wps.20375
Open DOI Search in Google Scholar Back to article
Cuijpers, P., & Smit, F. (2004). Subthreshold depression as a risk indicator for major depressive disorder: A systematic review of prospective studies. Acta Psychiatrica Scandinavica, 109(5), pp. 325–331. doi: 10.1111/j.1600-0447.2004.00301.x
Open DOI Search in Google Scholar Back to article
Cuijpers, P., Vogelzangs, N., Twisk, J., Kleiboer, A., Li, J., & Penninx, B. W. (2013). Differential mortality rates in major and subthreshold depression: Meta-analysis of studies that measured both. British Journal of Psychiatry, 202(1), pp. 22–27. doi: 10.1192/bjp.bp.112.112169
Open DOI Search in Google Scholar Back to article
Dirkzwager, A. J. E., Bramsen, I., & Van Der Ploeg, H. M. (2005). Factors associated with posttraumatic stress among peacekeeping soldiers. Anxiety, Stress & Coping, 18(1), pp. 37–51. doi: 10.1080/10615800412336418
Open DOI Search in Google Scholar Back to article
Eläketurvakeskus. (2022). Työkyvyttömyyseläkkeelle siirtyi ennätyksellisen vähän ihmisiä [Lehdistötiedote], STT Info. Available at: https://www.sttinfo.fi/tiedote/69934481/tyokyvyttomyyselakkeelle-siirtyi-ennatyksellisen-vahan-ihmisia?publisherId=1634 [accessed 3 September].
Search in Google Scholar Back to article
Finnish Defence Forces. (2026). International military crisis management. Available at: https://puolustusvoimat.fi/en/web/kansainvalinen-kriisinhallinta/operations. [accessed 15 August, 2025].
Search in Google Scholar Back to article
Forbes, D., O’Donnell, M., Brand, R. M., Korn, S., Creamer, M., & McFarlane, A. C., et al. (2016). The long-term mental health impact of peacekeeping: Prevalence and predictors of psychiatric disorder. BJPsych Open, 2(1), pp. 32–37. doi: 10.1192/bjpo.bp.115.001321
Open DOI Search in Google Scholar Back to article
Fried, E. I., Flake, J. K., & Robinaugh, D. J. (2022). Revisiting the theoretical and methodological foundations of depression measurement. Nature Reviews Psychology, 1(6), pp. 358–368. doi: 10.1038/s44159-022-00050-2
Open DOI Search in Google Scholar Back to article
Hoge, C. W., Castro, C. A., Messer, S. C., McGurk, D., Cotting, D. I., & Koffman, R. L. (2004). Combat duty in Iraq and Afghanistan, mental health problems, and barriers to care. New England Journal of Medicine, 351(1), pp. 13–22. doi: 10.1056/NEJMoa040603
Open DOI Search in Google Scholar Back to article
Honaker, J., King, G., & Blackwell, M. (2011). Amelia II: A program for missing data. Journal of Statistical Software, 45(7), pp. 1–47. Available at: https://www.jstatsoft.org/v45/i07/ [accessed 4 December, 2025]. doi: 10.18637/jss.v045.i07
Open DOI Search in Google Scholar Back to article
Jordan, A. H., Eisen, E., Bolton, E., Nash, W. P., & Litz, B. T. (2017). Distinguishing war-related PTSD resulting from perpetration- and betrayal-based morally injurious events. Psychological Trauma: Theory, Research, Practice and Policy, 9(6), pp. 627–634. doi: 10.1037/tra0000249
Open DOI Search in Google Scholar Back to article
Kaikkonen, N. M., & Laukkala, T. (2016). International military operations and mental health—a review. Nordic Journal of Psychiatry, 70(1), pp. 10–15. doi: 10.3109/08039488.2015.1048718
Open DOI Search in Google Scholar Back to article
Kampman, O., Heiskanen, T., Holi, M., Huttunen, M. O., Tuulari, J., & Aarninsalo, P., et al. (2017). Masennus. Duodecim.
Search in Google Scholar Back to article
Kendler, K. S., Zachar, P., & Craver, C. (2011). What kinds of things are psychiatric disorders? Psychological Medicine, 41(6), pp. 1143–1150. doi: 10.1017/S0033291710001844
Open DOI Search in Google Scholar Back to article
Litz, B. T., Orsillo, S. M., Friedman, M., Ehlich, P., & Batres, A. (1997). Posttraumatic stress disorder associated with peacekeeping duty in Somalia for U.S. military personnel. American Journal of Psychiatry, 154(2), pp. 178–184. doi: 10.1176/ajp.154.2.178
Open DOI Search in Google Scholar Back to article
Litz, B. T., Plouffe, R. A., Nazarov, A., Murphy, D., Phelps, A., & Coady, A., et al. (2022). Defining and assessing the syndrome of moral injury: Initial findings of the moral injury outcome scale consortium. Frontiers in Psychiatry, 13, p. 923928. doi: 10.3389/fpsyt.2022.923928
Open DOI Search in Google Scholar Back to article
Litz, B. T., Stein, N., Delaney, E., Lebowitz, L., Nash, W. P., & Silva, C., et al. (2009). Moral injury and moral repair in war veterans: A preliminary model and intervention strategy. Clinical Psychology Review, 29(8), pp. 695–706. doi: 10.1016/j.cpr.2009.07.003
Open DOI Search in Google Scholar Back to article
Maguen, S., Litz, B. T., Wang, J. L., & Cook, M. (2004). The stressors and demands of peacekeeping in Kosovo: Predictors of mental health response. Military Medicine, 169(3), pp. 198–206. doi: 10.7205/MILMED.169.3.198
Open DOI Search in Google Scholar Back to article
Mangiafico, S. (2024). rcompanion: Functions to Support Extension Education Program Evaluation. Version 2.4.35. Rutgers Cooperative Extension. Available at: https://CRAN.R-project.org/package=rcompanion [accessed 4 December, 2025].
Search in Google Scholar Back to article
Nordstrand, A. E., Bøe, H. J., Holen, A., Reichelt, J. G., Gjerstad, C. L., & Hjemdal, O. (2019). Danger- and non-danger-based stressors and their relations to posttraumatic deprecation or growth in Norwegian veterans deployed to Afghanistan. European Journal of Psychotraumatology, 10(1), p. 1601989. doi: 10.1080/20008198.2019.1601989
Open DOI Search in Google Scholar Back to article
Nordstrand, A. E., Noll, L., Huffman, A. H., Gjerstad, C. L., Tveitstul, T., & Reichelt, J., et al. (2025). Killing in combat as a potentially morally injurious event: The diverging psychological impact of killing on peacekeepers and combat-oriented troops. Armed Forces & Society, 52(3), pp. 904–934. doi: 10.1177/0095327X251321389
Open DOI Search in Google Scholar Back to article
R Core Team. (2021). R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing. Available at: https://www.R-project.org/ [accessed 4 December, 2025].
Search in Google Scholar Back to article
Raju, M. S. V. K. (2014). Psychological aspects of peacekeeping operations. Industrial Psychiatry Journal, 23(2), pp. 149–156. doi: 10.4103/0972-6748.151693
Open DOI Search in Google Scholar Back to article
Revelle, W. (2023). psych: Procedures for Personality and Psychological Research. Version 2.3.6. Evanston, Illinois: Northwestern University. Available at: https://CRAN.R-project.org/package=psych [accessed 4 December, 2025].
Search in Google Scholar Back to article
Rizopoulos, D. (2006). ltm: An R package for latent variable modeling and item response theory analyses. Journal of Statistical Software, 17(5), pp. 1–25. doi: 10.18637/jss.v017.i05
Open DOI Search in Google Scholar Back to article
Robinaugh, D. J., Hoekstra, R. H. A., Toner, E. R., & Borsboom, D. (2020). The network approach to psychopathology: A review of the literature 2008–2018 and an agenda for future research. Psychological Medicine, 50(3), pp. 353–366. doi: 10.1017/S0033291719003404
Open DOI Search in Google Scholar Back to article
Rodríguez, M. R., Nuevo, R., Chatterji, S., & Ayuso-Mateos, J. L. (2012). Definitions and factors associated with subthreshold depressive conditions: A systematic review. BMC Psychiatry, 12(1), p. 181. doi: 10.1186/1471-244X-12-181
Open DOI Search in Google Scholar Back to article
Sahramäki, J., Kuivanen, K., Törmä, L., & Simola, P. (2024). The psychological well-being of Finnish peacekeeping veterans post-deployment. Journal of Veterans Studies, 10(2), pp. 41–55. doi: 10.21061/jvs.v10i2.468
Open DOI Search in Google Scholar Back to article
Saito, T., Shigemura, J., Kitano, M., Waki, F., & Nagamine, M. (2025). Healthy warrior effect with deployment to United Nations peacekeeping operation: A longitudinal study among Japan ground self-defense forces. Military Medicine, 190(5–6), pp. e924–e929. doi: 10.1093/milmed/usae449
Open DOI Search in Google Scholar Back to article
Salokangas, R. K., Poutanen, O., & Stengård, E. (1995). Screening for depression in primary care. Development and validation of the depression scale, a screening instrument for depression. Acta Psychiatrica Scandinavica, 92(1), pp. 10–16. doi: 10.1111/j.1600-0447.1995.tb09536.x
Open DOI Search in Google Scholar Back to article
Sareen, J., Stein, M. B., Thoresen, S., Belik, S. L., Zamorski, M., & Asmundson, G. J. (2010). Is peacekeeping peaceful? A systematic review. Canadian Journal of Psychiatry. Revue Canadienne de Psychiatrie, 55(7), pp. 464–472. doi: 10.1177/070674371005500710
Open DOI Search in Google Scholar Back to article
Shemeikka, R., Alitalo, E., Ilvonen, K., Pietilä, P., Ryhänen, T., Sihvonen, A.-P., et al. (2022). Sotilaallisessa kriisinhallintatehtävässä palvelleiden kokonaisvaltaisen kuntoutuksen ja tuen tarve Suomessa. Oulunkylän kuntoutuskeskus sr, Helsinki.
Search in Google Scholar Back to article
Souza, W. F., Figueira, I., Mendlowicz, M. V., Volchan, E., Portella, C. M., & Mendonça-de-Souza, A. C., et al. (2011). Posttraumatic stress disorder in peacekeepers: A meta-analysis. Journal of Nervous & Mental Disease, 199(5), pp. 309–312. doi: 10.1097/NMD.0b013e3182175180
Open DOI Search in Google Scholar Back to article
United Nations. (2025). Contributions to UN Peacekeeping Operations by Country and Post. Available at: https://peacekeeping.un.org/en/contributions-to-un-peacekeeping-operations-country-and-post-september-2025 [accessed 4 December, 2025].
Search in Google Scholar Back to article
van der Wal, S. J., Geuze, E., & Vermetten, E. (2023). Long-term risk for mental health symptoms in Dutch ISAF veterans: The role of perceived social support. Psychological Medicine, 53(8), pp. 3355–3365. doi: 10.1017/S0033291721005389
Open DOI Search in Google Scholar Back to article
Warner, C. H., Appenzeller, G. N., Grieger, T., Belenkiy, S., Breitbach, J., Parker, J., Warner, C. M., & Hoge, C. (2011). Importance of anonymity to encourage honest reporting in mental health screening after combat deployment. Archives of General Psychiatry, 68(10), pp. 1065–1071. doi: 10.1001/archgenpsychiatry.2011.112
Open DOI Search in Google Scholar Back to article
Wickham, H. (2016). ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag, New York.
Search in Google Scholar Back to article
Wickham, H., François, R., Henry, L. and Müller, K. (2021). dplyr: A Grammar of Data Manipulation. Version 1.0.7. Available at: https://CRAN.R-project.org/package=dplyr [accessed 4 December, 2025].
Search in Google Scholar Back to article
Wickham, H., Miller, E. and Smith, D. (2023). haven: Import and Export ‘SPSS’, ‘Stata’ and ‘SAS’ Files. Version 2.5.2. Available at: https://CRAN.R-project.org/package=haven [accessed 4 December, 2025].
Search in Google Scholar Back to article
Yarvis, J. S., & Schiess, L. (2008). Subthreshold posttraumatic stress disorder (PTSD) as a predictor of depression, alcohol use, and health problems in veterans. Journal of Workplace Behavioral Health, 23(4), pp. 395–424. doi: 10.1080/15555240802547801
Open DOI Search in Google Scholar Back to article

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DOI: https://doi.org/10.2478/jms-2026-0003 | Journal eISSN: 1799-3350 | Journal ISSN: 2242-3524

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Language: English

Submitted on: Dec 5, 2025

Accepted on: Aug 19, 2026

Published on: Oct 30, 2026

Published by: National Defense University

In partnership with: Paradigm Publishing Services

Publication frequency: 1 issue per year

Keywords:

subclinical depression,

depression

Related subjects:

History,

© 2026 Alex Siira, Toni Survonen, Petteri Simola, Sami Määttä, published by National Defense University
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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