Depression and Associated Risk Factors Among Emergency Medicine Interns: Results from a National Longitudinal Cohort Study

Objective: Despite depression being common in residents, there are no published studies on the prevalence and risk factors for depression in emergency medicine (EM) interns. Our objectives were to explore the prevalence of depression among EM interns and to identify risk factors for depression including sleep, work hours, rotation type, race, ethnicity, sex, and age.

Methods: The Intern Health Study is a national longitudinal cohort study on intern mental health in all specialties. Secondary analysis was performed for EM interns only in this study. Data were collected from 2007 to 2021 and study participants completed a pre-intern year baseline survey and quarterly surveys throughout intern year, which included demographics and information on depressive symptoms, work hours, sleep, and rotation specifics. Depression severity was objectified using the Patient Health Questionnaire (PHQ9) with scores of 10 and higher meeting criteria for moderate to severe depression.

Results: A total of 1123 EM interns completed all surveys. The prevalence of moderate to severe depression among EM interns before starting internship was 4.8%. At Months 3, 6, 9, and 12 of intern year, the prevalence of moderate to severe depression was 17.8%, 20.5%, 20.8%, and 18.8%, respectively. PHQ9 scores were significantly higher at Month 3 of intern year compared to pre-intern year, but there were no differences at subsequent time points during intern year ( < 0.001). Females were more likely to have PHQ9 scores of 10 or above at all time points ( < 0.001). Clinical rotation type had a significant effect on PHQ9 scores, with intensive care unit rotations having a significantly higher PHQ9 score than other rotations ( < 0.001). Pearson's correlation revealed significant weak positive correlations between work hours and PHQ9 at each time point ( = 0.195, 0.200, 0.202, 0.243) and significant weak negative correlations between sleep hours and time off with PHQ9 (-0.162, -0.223, -0.180, -0.178; all  < 0.001).

Conclusions: Many EM interns experience moderate to severe depression. Female EM interns are more likely to be depressed than male interns. Numerous factors influence depression scores for interns, many of which are modifiable.