People who work overtime may have a higher chance of developing depression, according to a new study.
The study of British civil servants found that those who worked more than 11 hours per day were almost two-and-a-half times more likely to develop symptoms of depression than people who worked seven or eight hours per day.
"I had an everyday observation that many people seem to work excessive hours and I thought it might be worth studying whether there are any adverse effects related to that," said study researcher Dr. Marianna Virtanen, a professor at the Finnish Institute of Occupational Health.
Virtanen's previous research showed a correlation between long working hours and sleep disturbances, psychological distress and anxiety.
"These may be early signs or correlates of depression," she said.
Long hours and depression
The researchers analyzed data from about 2,000 middle-aged people who participated in the Whitehall II study, a long-term study of British civil servants that began in 1985. The study included people who had not reported depression in an early phase of the study, and who maintained full-time employment.
They found that 38 of 1,105 people who reported working seven to eight hours developed depression, whereas 10 of 227 people working more than 11 hours did.
The study also found that although in general, it was men who were in relationships and held higher job positions who worked the longest hours, younger women with lower job positions or other chronic diseases were also at risk.
The researchers took into account other factors that could affect a person's chances of developing depression, including age, sex, socioeconomic status, alcohol consumption and physical health.
"I'm not surprised by the findings," said Ronald Burke, a professor at York University in Canada who studies health, work intensity and work addiction. "Long work hours keep people away from activities that contribute to psychological health: family, friends, community, leisure, self-development and recovery." Burke was not involved in the study.
Health and the workplace
Virtanen said that there are also other factors for depression not taken into account in the study.
"Depression is a multifactorial disorder," she said. "An ideal study would be to have data to control for financial situation, family relationships," and other factors that can lead to a person working overtime.
Burke would have liked to see a measure of "work intensity" included.
"We have found that work intensity is a stronger predictor of psychological health than hours worked," he said. "Work intensity would be a broader measure of job strain than the one used in this study."
In the future, Virtanen said she hopes to examine data from other groups of people to see how working long hours may be related to chronic diseases, such as cancer.
Based on her research, she said she advocates for workplaces to place less pressure on employees, and to have shorter hours. She advises workers to "make a distinction between work and leisure, not skip holidays, take care of health and well-being, especially sleep and exercise."
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