Post-traumatic stress disorder in peacekeepers: a systematic literature review and meta-analysis.

Background: In peacekeeping operations, soldiers are often exposed to the same traumatic factors as in conventional war and may also be subject to physical risks and psychological stressors associated with post-traumatic stress disorder (PTSD). According to the Conservation of Resources Theory (COR), PTSD stems from resource depletion and inadequate restoration. Objectives: To discuss and meta-analyse PTSD-related factors among peacekeepers, based on the COR theory, framing them as resources or loss/threat of loss of resources. Methods: A systematic literature search was performed with relevant keywords, 51 articles were reviewed and 21 of them meta-analysed. Results: Factors mentioned in prior reviews, reinforced by ours, include: family/community and military support as resources; single marital status, female gender, serving in infantry, and longer time since deployment as lack of resources. Factors mentioned in prior reviews, confirmed by our meta-analysis, include: education, rank, and problem-focused coping as resources; negative perceptions about deployment, combat/trauma exposure, deployment stressors, and deployment duration as lack of resources. Factors overlooked in prior reviews include: age as a resource; negative life events, and negative social interactions as lack of resources. Comorbidities include: physical health problems, post-deployment impact on functioning, and post-deployment psychopathology (e.g., depression, substance use). Conclusions: Significantly more individual than contextual factors were identified. While some factors inherent to missions (e.g., combat exposure, deployment stressors) cannot be mitigated, others are crucial to prevent peacekeepers' PTSD (e.g., coping strategies, deployment duration, perceptions about deployment, social interactions, support during deployment) and to inform selection and monitoring by the Armed Forces (e.g., pre-, during and post-deployment psychopathology). However, the findings should be interpreted with caution due to limitations (e.g., publication bias, study heterogeneity) that may have affected the generalizability and strength of the recommendations.