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.