Effects of continuous traumatic stress and coping efficacy on mental health outcomes during an ongoing war in Ukraine

War profoundly affects the well-being of civilian populations and shapes subsequent mental health outcomes. This study aimed to investigate the effects of continuous traumatic stress (CTS) and coping efficacy on mental health outcomes among adults in Ukraine amid ongoing warfare over time. We examined how changes in CTS responses, coping efficacy, and stressful life events predicted posttraumatic stress disorder (PTSD) symptoms and broad mental health outcomes (depression, anxiety, insomnia, well-being). Participants were 157 adults who experienced war-related stress and completed two online surveys approximately 12 months apart. Moderately small but significant symptom reductions were observed, ds = 0.18-0.32, ps = .005-.026. Structural equation models analyzing the associations between initial status and changes in CTS, coping efficacy, and stressful life events and Time 2 PTSD symptoms and broad mental health outcomes explained most of the variance in PTSD symptoms and broad mental health outcomes, R² = .84‒.85. Higher initial severity and worsening CTS responses over time predicted higher PTSD symptom severity, standardized estimate (Est_std) = 0.29‒0.32, ps = .001‒.006, and poorer broad mental health outcomes, Est_std = 0.25‒0.28, ps = .001‒.016. Increased stressful life event exposure was linked to worse broad mental health outcomes, Est_std = 0.16, p = .001. Improvements in coping efficacy predicted superior broad mental health outcomes, Est_std = -0.43, p < .001. Assessing and addressing the impact of CTS, considering the toll of stressful life events, and enhancing coping efficacy may help to optimize service delivery in ongoing war environments.