Most people could identify with work-related stress at some point in their lives, whether it results from unfairness in the workplace, a perpetually unsatisfied boss, or an overwhelming workload. While the sheer amount of work is a common subject of workplace banter among employees, it's rarely a cause of work-related depression. Instead, onset of depressive symptoms is more commonly associated with the work environment and employee-boss relationship, according to a new study.

The Danish study surveyed over 4,000 public employees, who worked at schools, hospitals, nurseries, and more. Researchers found that workers’ perception of their environment, relationships with other workers, their bosses, and overall equality in the workplace — or “justice” — was linked to the onset of depressive symptoms. Interestingly, the researchers found that higher levels of the stress hormone, cortisol, were associated with a lower risk for depression.

“We may have a tendency to associate depression and stress with work pressure and workload; however, our study shows that the workload actually has no effect on workplace depression,” Matias Brodsgaard Grynderup, Ph.D., of Aarhus University, told ScienceNordic. “This suggests that the risk of workplace depression cannot be minimized by changing the workload. Other factors are involved, and it is these factors that we should focus on in the future.”

Grynderup and colleagues also tested participants’ saliva for concentrations of the stress hormone cortisol. Two years later, follow-up interviews and tests showed that workload had no effect on depression, but work environment and relationships did. It seemed harder to get things done when employees were unhappy with workplace conditions. “Depression can make work assignments appear insurmountable, even though the depression was not caused by the workload,” Grynderup said.

Contrary to previous studies, higher levels of cortisol were associated with a lower risk for depression, the researchers found. “Our results actually show that high cortisol levels are associated with a low risk of developing depression,” Grynderup said. “This means that we may be able to use cortisol measurements as an indicator of the risk of developing depression.”

A July 2013 Gallup poll found that an average of 12 percent of all U.S. workers reported being diagnosed with depression at some point in their lives, with half of them saying that they were currently being treated. The poll found that the cost of workplace depression — resulting from missed workdays — cost employers more than $23 billion a year. Both Gallup and the study authors suggested that employers direct their focus on employee engagement.

“When employees’ sense of justice plays such a central role in minimizing risk of depression, this is probably the area that preventative work should focus on,” Grynderup said. “I recommend a management style in which there is a clearly expressed wish to treat employees properly — combined with a transparent organizational structure.”

Source: Grynderup M, Mors O, Hansen A, et al. Work-unit measures of organisational justice and risk of depression — a 2-year cohort study. Occupational and Environmental Medicine. 2013.