A comprehensive Swedish overview of 42 studies examines the link between working conditions and depression. The overview concludes that pressure at work increases the risk of depression. Five of the studies show clear causality between high psychological pressure and depression. The overview also found that other factors such as job strain and the combination of low control and high performance demands have a small effect on the risk of developing depression.
The relationship between work-related pressure and depression has been extensively studied recently in both national and international studies. However, there are differences in both the results and quality of the studies. A comprehensive Swedish overview of 42 studies attempts to find a uniform answer to the question of whether work-related pressure causes depression.
Five studies were found to be of exceptional quality. These studies did not rely on subjective answers from workers but rather on quality indicators such as job exposure matrices based on profession titles and hospital patient overcrowding.
The review, Can working conditions cause depression? A systematic review of longitudinal studies in the scientific literature from 1998 to 2012 (in Swedish, 425Kb PDF), is the third in the Work and Health series of papers published by the Department of Employment and Environmental Medicine at the University of Gothenburg. It concludes that pressure at work increases the risk of depression.
The overview shows that different studies report contradictory results, but the main findings of the overview are that:
The overview also identifies the different types of work-related pressure described in the 42 studies. These include psychological pressure, pressure due to lack of control, weak social support, low decision-making authority, and the combination of low control and high performance demands, commonly referred to as job strain.
The studies identified as being of the highest quality showed strong support for the hypothesis that psychological pressure increased the risk of developing depression. They also suggested that job strain increased the risk of depression for men, but not for women. There is also support for a causal relationship between emotional pressure and depression in women. However, studies show no support, or weak support, for the impact of lack of control, weak social support, or low decision-making authority on the risk of developing depression.
The results of studies of lower quality are ambiguous. The review authors propose that one explanation for this is that depressed workers exaggerate their reports of exposure to work-related pressure, or otherwise subjectively skew the results.
Bengt Järvholm, co-author of the overview, argues that despite the fact that the overview fails to conclude strong causality between types of work-related pressure other than psychological pressure, the results do not imply that such relationships do not exist. It might instead reflect the fact that studies of pressure types other than psychological pressure are both less numerous and of poorer quality than studies on psychological pressure.
The overview was carried out by dividing the 42 articles into three groups based on the quality of the estimates. The two lower-quality groups include or consist of self-reported worker estimates. The group of studies that were of highest quality used non-subjective measurements such as job exposure matrices based on profession titles and hospital patient overcrowding.
The review reports that one characteristic of depression is that it is hereditary. The overview suggests that more research is needed to investigate where people with such genetic features are recruited. It also suggests more research on the timeframe of pressure exposure needed for an increasing depression risk level.
Three of the most highly regarded studies in the overview put this timeframe at between less than a year and less than three years. According to the overview, this timeframe does not coincide with traditional depression epidemiology and therefore more research is needed.
According to the overview, mental distress is the second most common reason for workers taking time off work in Sweden, accounting for 17% of all sick leave. Absence for this reason also results in a longer median period of sick leave than for many other causes. Mental health therefore has a significant economic impact on the Swedish economy. The review finds support for the view that psychological pressure in the workplace increases the risk of depression.
Further research developments are needed on the timeframe of exposure to such pressure before we can fully understand to what extent work-related pressure increases the risk of depression. Further research is also needed on the recruitment patterns of people who might have a higher genetic predisposition towards depression.
Lundberg, I., Allebeck, P., Forsell, Y., Westerholm, P. (2013), ‘Systematiska kunskapsöversikter: Kan arbetsvillkor orsaka depressionstillstånd? En systematisk översikt över longitudinella studier i den vetenskapliga litteraturen 1998–2012’ [Can working conditions cause depression? A systematic review of longitudinal studies in the scientific literature from 1998 to 2012], Skriftserien Arbete och Hälsa [Work and Health Series], No. 3, Department of Employment and Environmental Medicine, University of Gothenburg, Gothenburg.
Angelica Idenving and Emilia Johansson, Oxford Research