Pretorius, TyronePadmanabhanunni, Anita2026-03-242026-03-242025Pretorius, T. and Padmanabhanunni, A., 2025. Sleep and Mood as Mechanisms Linking Trauma Exposure to Alcohol Use in South African First Responders: A Serial Mediation Analysis. OBM Neurobiology, 9(4), pp.1-14.https://doi.org/10.21926/obm.neurobiol.2504308https://hdl.handle.net/10566/22103First responders are routinely exposed to traumatic events in the line of duty, placing them at heightened risk for adverse mental health outcomes, including substance use. This study investigated the psychological mechanisms linking trauma exposure to alcohol use, specifically examining the serial mediating roles of insomnia and depression. A sample of 429 first responders (309 police officers and 120 paramedics) from the Western Cape, South Africa, completed an online survey comprising the Life Events Checklist-5, Insomnia Severity Index, Patient Health Questionnaire-9, and the Alcohol Use Disorders Identification Test. Mediation analysis was conducted using the Hayes PROCESS macro (Model 6) in SPSS. Trauma exposure was significantly associated with increased levels of insomnia, depressive symptoms, and alcohol use. Mediation analysis revealed that both insomnia and depression independently fully mediated the relationship between trauma exposure and alcohol use. Additionally, a significant serial mediation pathway was observed, indicating that trauma exposure led to insomnia, which in turn contributed to depression, ultimately resulting in higher alcohol use. These findings highlight the central role of sleep disturbances and depressive symptoms in the trauma–alcohol use nexus among first responders. Interventions that address insomnia may not only alleviate depressive symptoms but also serve to mitigate harmful alcohol use in this high-risk population.enalcohol usedepressionFirst respondersinsomniaserial mediationArticle