The role of PTSD-depression comorbidity in long-term mental health sequalae of the October 7th terror attack in Israel: A nationwide prospective study

Introduction: The October 7, 2023, attack engendered extensive mental pain and can be considered a mass trauma that affected most Israeli citizens. This study investigates the long-term psychological impact of probable post-traumatic stress disorder and major depressive disorder (PTSD-MDD) one month after October 7th, on anxiety, depression, PTSD, and complex PTSD (CPTSD) symptoms as well as on suicidal ideation, and life satisfaction oneyear post-attack among Israeli civilians. Methods: Using a nationally representative cohort of 600 participants (302 women, 50.3 %) aged 18-85 (Mage = 41.02, SD = 13.79), data were collected two months pre-attack (T1), one-month post-attack (T2), and one-year post-attack (T3). Using validated self-report measures, probable diagnostic groups at T2 (no diagnosis, PTSD alone, depression alone, and probable PTSD-MDD comorbidity) were examined as predictors of mental health outcomes at T3, including anxiety, depression, PTSS, CPTSD, suicidal ideation, and life satisfaction. Baseline symptom levels (T1) as well as demographics and trauma-related variables were controlled during the analyses. Results: Probable PTSD-MDD at T2 significantly predicted severe psychological outcomes at T3, including anxiety, depression, PTSS, and suicidal ideation. Life satisfaction was lowest among probable PTSD-MDD participants and highest in those without diagnoses. Notably, probable PTSD-MDD demonstrated greater stability over time compared to single diagnoses, underscoring their persistence. Changes in probable diagnostic categories between T2 and T3 highlighted the dynamic yet challenging recovery trajectories particularly for comorbid conditions. Discussion: The findings underscore the amplifying effect of probable PTSD-MDD comorbidity on psychological distress and reduced life satisfaction. These results underscore the need for integrative, trauma-informed interventions targeting comorbid populations to optimize recovery pathways.