Reducing the level of stress that comes along with work — if, indeed, it is possible to do so — may not only be beneficial, but may actually stave off the risk of serious depression. On average, about 4.4% of the population suffers from major depression — and, according to a new study in the American Journal of Epidemiology, depression may be tightly linked to stress on the job.

Even more telling was the fact that among those whose reports of job strain changed over the six-year period, so did their risk of depression.

The research team, led by JianLi Wang at the University of Calgary, followed almost 4,900 people who took part in the Canadian National Population Health Study. The participants reported the level of stress associated with their jobs — also known as job strain — in 1994−1995 and 2000−2001.

Participants fell into four categories: those who reported high job strain at both time points, those who reported low job strain at both points, those who reported high job strain at the first point and low job strain at the second, and those who reported low job strain first and high job strain later.

Eight percent of the individuals who were stressed at both times suffered from major depression; but only 4% of the individuals who reported low stress at both times were depressed.

Even more telling was the fact that among those whose reports of job strain changed over the six −year period, so did their risk of depression. Participants whose job strain increased over the years were 6.9% more likely to suffer from depression in the end, while the depression risk of those whose stresses decreased was only 4.4%.

"These results indicated that interventions targeted to reducing job strain may significantly reduce the risk of depression," says Wang.

The researchers also found an interesting link between how healthy the participants rated themselves and their likelihood of depression: those who rated themselves as being very healthy were at greater risk for depression, while those who rated themselves as less healthy were at less risk. Wang and his team conclude that those who ranked themselves as less healthy "may have accepted the reality of having poor health and of exposure to various risk factors for health."

The researchers note that stress level from work can change relatively quickly over time, so future studies should look at the connection between job strain and depression in shorter periods of time than were assessed here.