Endocannabinoids Mediate Racial/Ethnic Discrimination Prediction of Posttraumatic Stress Disorder Symptoms Moderated...

Individuals from marginalized ethnoracial groups face higher risk for posttraumatic stress disorder (PTSD) symptoms, exacerbated by experiencing racial/ethnic discrimination. Previous work separately explored the endocannabinoid (eCB) system and functional connectivity response to stress/trauma and suggested that experiences of chronic minority stress, such as racial discrimination, contribute to eCB tone and resting-state functional connectivity. We explored how circulating eCB tone, in conjunction with resting-state connectivity, contributes to increased risk for PTSD symptoms following trauma among individuals experiencing discrimination.

Black/African Americans (n = 74; mean age = 33.81 years) were recruited from a level 1 trauma center. Correlational and linear models explored whether experiences of racial/ethnic discrimination (Perceived Ethnic Racial Discrimination Questionnaire), eCB (AEA [N-arachidonoylethanolamine], 2-AG [2-arachidonoylglycerol]) concentrations, default mode network (DMN) functional connectivity, or salience network (SN) functional connectivity were associated with PTSD symptoms (PTSD Checklist for DSM-5). Then, we explored moderated mediation models in which discrimination predicted PTSD symptoms with eCB concentration as a mediator and functional connectivity as a moderator.

Discrimination was correlated with PTSD symptoms (r = 0.50), serum AEA concentration (r = 0.43), and DMN connectivity (r = 0.23). When including urine Δ⁹-tetrahydrocannabinol, lifetime trauma, age, and sex as covariates, AEA concentration was associated with PTSD symptoms (r = 0.30) and DMN connectivity (r = 0.24). AEA mediated the relationship between discrimination and PTSD symptoms, and SN connectivity moderated this mediation (B = 52.46).

Our findings highlight how racial/ethnic discrimination impacts neurobiological systems that may lead to increased vulnerability for PTSD symptoms following an injury. Future work should continue to explore biological factors associated with the socioecological model of health as mechanisms of risk for adverse outcomes following trauma.