Long-Term Outcomes and Determinants of New-Onset Mental Health Conditions After Trauma

Importance Evidence suggests that trauma-related mortality and morbidities may follow a multiphasic pattern, with outcomes extending beyond hospital discharge. Objectives To determine the incidence of having new mental health conditions after the first (or index) trauma admission and their association with long-term health outcomes. Design, Setting, and Participants This population-based, linked-data cohort study was conducted between January 1994 and September 2020, with data analyzed in April 2024. Participants were adult patients with trauma admitted to 1 of the 5 adult trauma hospitals in Western Australia. All patients with major trauma with an Injury Severity Score (ISS) greater than 15 were included. For each patient with major trauma, 2 patients with trauma with a lower ISS (<16) were randomly selected. Exposure A new mental health condition recorded in either subsequent public or private hospitalizations after trauma admission. Main Outcomes and Measures The primary outcomes were the associations between new mental health conditions after trauma and subsequent risks of trauma readmission, suicide, and all-cause mortality, as determined by Cox proportional hazards regression. Logistic regression was used to determine which factors were associated with developing a new mental health condition after trauma. Results Of 29 191 patients (median [IQR] age, 42 [27-65] years; 19 383 male [66.4%]; median [IQR] ISS, 9 [5-16]; 9405 with ISS >15 and 19 786 with ISS <16) considered, 2233 (7.6%) had a mental health condition before their trauma admissions. The median (IQR) follow-up time after the index trauma admission was 99.8 (61.2-148.5) months. Of 26 958 patients without a prior mental health condition, 3299 (11.3%) developed a mental health condition subsequently, including drug dependence (2391 patients [8.2%], with 419 patients [1.4%] experiencing opioid dependence) and neurotic disorders (1574 patients [5.4%]), including posttraumatic stress disorder. Developing a new mental health condition after trauma was associated with subsequent trauma readmissions (adjusted hazard ratio [aHR], 1.30; 95% CI, 1.23-1.37; P < .001), suicides (aHR, 3.14; 95% CI, 2.00-4.91; P < .001), and all-cause mortality (aHR, 1.24; 95% CI, 1.12-1.38; P < .001). Younger age, unemployment, being single or divorced (vs married), Indigenous ethnicity, and a lower socioeconomic status were all associated with developing a new mental health condition after the first trauma admission. Conclusions and Relevance This cohort study of 29 191 patients with trauma found that mental health conditions after trauma were common and associated with an increased risk of adverse long-term outcomes, indicating that mental health follow-up of patients with trauma, particularly those from vulnerable subgroups, may be warranted.