Moral injury and cannabis use disorder among Israeli combat veterans: The role of depression and perceived social support

Introduction: Cannabis use is highly common among military combat veterans, who are also inclined toward developing Cannabis Use Disorder (CUD). The present study examined the association between Moral Injury (MI), which may occur following combat-related acts that violate one's deep moral beliefs, and CUD, as well as the mediating role of depression and the moderating role of perceived social support. Methods: Participants were 215 Israel Defense Forces male combat veterans discharged from military service within the past five years, who reported using cannabis regularly (>= 3 days weekly) during the past six months. Participants completed a set of validated self-report questionnaires assessing MI, CUD, depression and perceived social support. Results: Results indicated that MI-perpetration by self and MI-betrayal were positively associated with CUD. Additionally, serial mediation analyses indicated that the associations between MI-self and betrayal and CUD were mediated by depression (direct effect: beta = 0.13, p = 0.1, and beta = 0.20, p = .04, respectively). Furthermore, moderation analyses indicated that the association between MI and CUD was significant only among participants with average or high levels of perceived social support (for support by a significant other: b = 0.13, p = .006 and b = 0.22, p < .001 for MI-self and betrayal, respectively; for support by family: b = 0.13, p = .009 for MI-betrayal; and for support by friends: b = 0.1, p = .044 for MI-self). Conclusions: MI and its association with CUD should be addressed in clinical settings when working with combat veterans.