Workplace Injury and Mental Health Outcomes.

Importance: Workplace injury is a widespread problem that impacts mental health and quality of life and places a substantial burden on employers and the health care system. Objective: To determine whether mental disorder rates differ following workplace injury compared with injuries outside the workplace. Design, Setting, and Participants: This retrospective cohort study assessed individuals hospitalized for an injury requiring surgery between January 1, 2002, and December 31, 2018, with a 2-year follow-up period using population-based administrative data in Manitoba, Canada. Analyses were completed June to July 2021. This study compared 2 cohorts: individuals with a workplace injury matched 1:5 on sex, age, geographical region, and surgical procedure code with individuals with a nonworkplace injury in the general population. Exposure: Traumatic physical injury that required surgery with anesthetic. Main Outcomes and Measures: The outcome of interest was a diagnosis of mental disorder (anxiety, depression, substance abuse, suicide attempt, and any mental disorder), measured 2 years prior to and following injury. Results: In this cohort study, 7556 individuals (mean [SD] age, 44.8 [13.3] years; 5721 [75.7%] male; 4624 individuals [61.2%] with urban residence; 4545 individuals [60.1%] with low income) with a workplace injury were compared with 28 901 matches from the general population. The workplace cohort had lower rates of all mental disorders (anxiety: adjusted rate ratio [ARR], 0.82; 95% CI, 0.77-0.87; depression: ARR, 0.78; 95% CI, 0.72-0.84; substance abuse: ARR, 0.63; 95% CI, 0.55-0.72; suicide attempt: ARR, 0.28; 95% CI, 0.11-0.70; and any mental disorder: ARR, 0.82; 95% CI, 0.78-0.86; all P < .0006) before their injury and for depression (ARR, 0.89; 95% CI, 0.82-0.95) and substance abuse (ARR, 0.83; 95% CI, 0.73-0.94) after their injury. The group × care period interaction term was significant for anxiety (P < .0001) and any mental disorder (P < .0001), suggesting that individuals with workplace injuries had worse mental disorder outcomes over time than individuals with nonworkplace injuries. Conclusions and Relevance: This cohort study found that the mental health trajectory from the preinjury to postinjury period was worse for individuals with a workplace injury compared with those injured outside the workplace. These findings suggest that there may be features unique to the workplace and/or injury claims and compensation processes that contribute to this pattern, which warrant further examination.