Unit cohesion during deployment and post-deployment mental health: is cohesion an individual- or unit-level buffer for combat-exposed soldiers?

• Published in: Psychological medicine 2022-01, Vol.52 (1), p.121-131
• Main Authors: Campbell-Sills, Laura, Flynn, Patrick J., Choi, Karmel W., Ng, Tsz Hin H., Aliaga, Pablo A., Broshek, Catherine, Jain, Sonia, Kessler, Ronald C., Stein, Murray B., Ursano, Robert J., Bliese, Paul D.
• Format: Article
• Language: English
• Subjects: Afghan Campaign 2001; Armed forces; Buffering; Combat experience; Deployment; Health problems; Humans; Individual differences; Intervention; Leadership; Mental depression; Mental disorders; Mental Health; Military personnel; Military Personnel - psychology; Original Article; Post traumatic stress disorder; Regression analysis; Risk Factors; Soldiers; Stress Disorders, Post-Traumatic - psychology; Suicidal Ideation; Suicide; Symptoms
• ISSN: 0033-2917; 1469-8978
• DOI: 10.1017/S0033291720001786

Unit cohesion may protect service member mental health by mitigating effects of combat exposure; however, questions remain about the origins of potential stress-buffering effects. We examined buffering effects associated with two forms of unit cohesion (peer-oriented horizontal cohesion and subordinate-leader vertical cohesion) defined as either individual-level or aggregated unit-level variables. Longitudinal survey data from US Army soldiers who deployed to Afghanistan in 2012 were analyzed using mixed-effects regression. Models evaluated individual- and unit-level interaction effects of combat exposure and cohesion during deployment on symptoms of post-traumatic stress disorder (PTSD), depression, and suicidal ideation reported at 3 months post-deployment (model 's = 6684 to 6826). Given the small effective sample size ( = 89), the significance of unit-level interactions was evaluated at a 90% confidence level. At the individual-level, buffering effects of horizontal cohesion were found for PTSD symptoms [ = -0.11, 95% CI (-0.18 to -0.04), < 0.01] and depressive symptoms [ = -0.06, 95% CI (-0.10 to -0.01), < 0.05]; while a buffering effect of vertical cohesion was observed for PTSD symptoms only [ = -0.03, 95% CI (-0.06 to -0.0001), < 0.05]. At the unit-level, buffering effects of horizontal (but not vertical) cohesion were observed for PTSD symptoms [ = -0.91, 90% CI (-1.70 to -0.11), = 0.06], depressive symptoms [ = -0.83, 90% CI (-1.24 to -0.41), < 0.01], and suicidal ideation [ = -0.32, 90% CI (-0.62 to -0.01), = 0.08]. Policies and interventions that enhance horizontal cohesion may protect combat-exposed units against post-deployment mental health problems. Efforts to support individual soldiers who report low levels of horizontal or vertical cohesion may also yield mental health benefits.