Moral Injury and Mental Health: A Systematic Review and Meta-Analysis

Certain events, termed potentially morally injurious events, can transgress an individual's existing moral framework and elicit morally injurious outcomes, which, in turn, can be associated with negative mental health outcomes. This systematic review and meta-analysis (Prospero ID-CRD42018104621) aimed to examine the relationship between moral injury outcomes and mental health. Fifty-nine articles, representing 50 independent samples, were reviewed, including for methodological quality. We found statistically significant relationships between all moral injury outcomes and mental health, with predominately moderate-large effect sizes observed. Relationships were typically stronger if studies measured moral injury outcomes only, compared with studies that included measurement of both exposure and outcomes. The Moral Injury subscales (Self, Others, and Betrayal) were also significantly related to poorer mental health. Overall, the meta-analytic results support reliable associations between moral injury outcomes and poorer mental health. Future research needs to diversify into nonmilitary populations, consider measurement tool selection, and strive for greater consensus regarding theoretical frameworks to direct this emerging research area.