Working Overtime Doubles Depression

People who work long hours have more than twice the risk of depression

/ Author:  / Reviewed by: Joseph V. Madia, MD

"All work and no play makes Jack a dull boy," goes the popular saying. Apparently, it also makes Jack a depressed boy. For people who work long hours, above the 40-hour-per-week average, the risk of becoming depressed is much greater.

And that increased risk of depression is high no matter how stressful the job.

This was clearly illustrated recently in Britain, where more than 2,000 civil servants were followed for six years. Those who put in an average of 11 hours per day or more at the office, had about two and a half times the odds of developing depression that their colleagues who clocked out after seven or eight hours.

Overtime and Depression

The British study used data from another long-running study called Whitehall II, which conducted research on employees from 20 different branches of civil service in London. Lead author Marianna Virtanen, Ph.D. from the Finnish Institute of Occupational Health in Helsinki and University College London, focused on 2,123 workers who were all evaluated as mentally healthy when they entered the study, between 1991 and 1993.

After six years, a little more than three percent of the employees had experienced clinical depression within the previous year. And the more overtime they worked, the more likely they were to be depressed.

The majority of the participating employees (52 percent) worked a normal seven-to-eight hour workday. 37 percent averaged nine or ten hours a day at the office, and 11 percent worked an average of 11 hours or more each day. For those 11 percent, they experienced greater depression at a rate of two and a half times their colleagues. This increased risk was present even after other factors such as alcohol and tobacco use, job strain and chronic physical diseases were accounted for.

"Data from middle-aged civil servants suggest that working long hours of overtime may predispose to major depressive episodes," Virtanen concluded. The study used the most rigorous standard for measuring depression, using the American Psychiatric Association's official criteria for clinical depression.

The research did have its limitations. First of all, only white-collar workers were included in the study, so the correlation between depression and overtime for blue-collar workers or those in the private sector has not been established. Also, the study didn't answer the question of how long does it take for long work hours to lead to depression. Does the risk increase after working long hours for a year? Or a month, or even a week?

Daniel Keeran, MSW, says that there could be a significant difference between higher and lower level employees - and that difference could be worse for low-level employees. "Top-level employees get more flexibility with hours, vacation time, and have more job security. Lower-level employees are paid less and worry about meeting expenses, and this negative thinking feeds depression." Keeran was not involved in the British study.

Overtime and Heart Disease

Virtanen's recent study built upon the Whitehall II study, which showed a strong correlation between long work hours and the risk of heart disease. In Whitehall, 6,000 civil servants in the U.K. with no previous history of heart disease were tracked for 11 years. During that period, 369 of them had heart attacks or angina, or died from heart disease.

After accounting for other factors such as age, sex, marital status and occupational level, the researchers found that those who worked three or four hours of overtime each day increased their risk for heart disease by a whopping 60 percent.

After those findings, Virtanen said, "Our findings suggest a link between working long hours and increased CHD [coronary heart disease] risk, but more research is needed before we can be confident that overtime work would cause CHD. In addition, we need more research on other health outcomes, such as depression and type 2 diabetes."

Virtanen theorizes that it may not be just the long hours themselves creating more depression and heart disease; it may also be related to the type of person who regularly works such long hours. People who regularly work 10 or more hours a day tend to be more "Type A" personalities, and are more competitive, aggressive and hostile, and may also have more trouble sleeping and be more prone to anxiety or depression.

"Lack of proper sleep and rest increases stress and anxiety which feeds negative thoughts that contribute to depression," Keeran adds.

The Hordaland Health Studies

The British studies weren't the first to show such a relationship; in two different studies in Norway in the 1990s, a definite link between overtime work and both depression and anxiety were found. The first Hordaland study was conducted in 1992-1993 and included 18,044 men and women in Western Norway.

The second study, done between 1997-1999, compared 1,350 overtime workers with a control group of 9,092 workers who did not work overtime. Researchers used self-reported information about lifestyle and work-related factors, and used the Hospital Anxiety and Depression Scale to rate the levels of these factors in the workers.

The study found that the overtime workers had significantly higher levels of anxiety and depression, and a higher prevalence of actual anxiety and depressive disorders, than those who worked normal hours. This was true for both men and women.

"Overwork can have additional far-reaching repercussions for health and safety, " says Barbara Long, M.D., Ph.D. and a private-practice psychiatrist in Atlanta. "Fatigue-related problems include memory, concentration, judgment, anger management, and the ability to operate machinery safely." These problems can lead to motor vehicle accidents and other serious workplace accidents, such as the 2005 BP operator error-related explosion that killed 15 and injured 170.

In 2010, OSHA began consider the need for specific limits on the work week for all workers. Even the medical profession, which used to work medical students, interns, and residents in excess of 80 hours a week, has recognized the dangers to patients when providers are fatigued due to overwork.

"Work is an important quadrant of life, but to be healthy, strive for balance by attending to the other three: physical, emotional, and spiritual," adds Dr. Long.

Review Date: 
February 1, 2012