Depression is a serious and common medical illness that negatively affects how individuals feel, think, and act. To date, working long hours has been tied primarily to severe burnout and stress. Now, a recent study has found that those who work long hours also have increased current and future risks of suffering depression.

The new study was published in the New England Journal of Medicine. Researchers from Michigan University set up their study with the help of over 17,082 participants who were first-year physicians recruited yearly from April to June 2009 to 2020. The average age of the doctors in the study was found to be 27 years, consisting of mostly women. Researchers obtained their data from the Intern Health Study where they analyze new medical school graduates to track their work hours, sleep as well as the likelihood of depression; while they round up their intern year. 

On a standard scale, the study authors found an average symptom increase of 1.8 points for those working 40 to 45 hours against 5.2 points for interns working over 90 hours a week. In addition, the result showed that less than 1 in 20 met the criteria for moderate to severe depression at the beginning of the intern year. Among the wide range of hours reported by the interns, 65 to 80 hours per week were found to be the most common work hour levels reported.

The team found that higher work hours were strongly linked to a greater rise in depression symptoms, making some of the first resident physicians fall into the severe or moderate depression range – serious enough to call for treatment. Taking into account that the research team used advanced statistical methods to emulate a randomized clinical trial, considering several other factors in doctors’ professional and private lives.

As a result, this led the team to conclude that the more hours a person works each week in a stressful job, the more their risk of depression rises.

It’s worth noting that their findings reveal that among all the stressors affecting physicians, working prolonged hours is the main contributor to depression. The study authors, therefore, highlight the need to cut down work hours for doctors each week.

In fact, the team suggests strongly that reducing the average number of work hours would have a significant impact on the extent to which interns tend to develop depression symptoms. Pursuing this further, they also add that the number of those who develop diagnosable depression will be largely decreased. “The key thing is to have people work fewer hours; you can more effectively deal with the stresses or frustrations of your job when you have more time to recover,” says study senior author, Amy Bohnert.

In conclusion, the authors see the need for studies on the mental states of workers to be conducted in other stressful and high-work-hour jobs. However, they believe a similar negative impact of long working hours on mental health would as well apply to other professions.

Written by

Medically Reviewed by