Depression Risk Rises With More Hours Worked, Study of US First-Year Physicians Finds

The more hours a first-year medical resident worked in a week, the higher their chances of developing depressive symptoms rose, according to study results published in the New England Journal of Medicine.

“Reduction in work hours has received only limited mention in the recent recommendations and policy statements addressing clinician well-being,” wrote Yu Fang, MSE, University of Michigan Medical School, and co-authors. “Our findings suggest that limiting the number of hours worked per week by residents has the potential to reduce rates of depression among early-career trainees.”

Using advanced statistical models informed by data from the Intern Health Study from 2009 to 2020, the research team simulated a randomized trial through emulated trial design. They used the Patient Health Questionnaire 9-item version (PHQ-9) to assess depressive symptoms 1 to 2 months before internships began, then followed up quarterly throughout the year.

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To evaluate how weekly work hours affected depression, researchers categorized weekly work hours into increasing groups, starting from 0-20 hours and going up to over 90 hours worked within one week. Standardization was used to estimate the mean change in PHQ-9 scores over the year.

At the outset of the study, the mean score of the interns’ PHQ-9 was 2.7±3.1 points. As assessed on a quarterly schedule, interns at the higher work levels displayed higher PHQ-9 total scores, with 33.4% of them meeting the criteria for depression when working 90 hours or more per week. For those who worked 40 to 45 hours per week, total PHQ-9 scores increased from baseline by 1.8 points. Those working 90 hours or more per week had their PHQ-9 scores increase 5.2 points from baseline.

“Specifically, the increase in symptom scores was almost 3 times as high in the highest work-hour category (>90 hours per week) as in the work-hour category of more than 40 and up to 45 hours per week, which is the category closest to the hours typical of most nonmedical professions,” Fang and co-authors concluded.

References

Fang Y, Lodi S, Hughes TM, et al. Work hours and depression in US first-year physicians. N Eng J Med 2022; 387: 1522-1524. DOIL: 10.1056/NEJMc2210365

Michigan Medicine at University of Michigan. In stressful jobs, depression risk rises with hours worked, study in new doctors finds. Press release. Newswise. Published online October 20, 2022.