A new study, led by Samuel Harvey, Associate Professor at the Black Dog Institute in Australia, investigates the association between job strain and mental health challenges. The results of the study, published in The Lancet Psychiatry, indicate that higher job strain increases one’s risk of developing a “common mental disorder” by age 50.
“The present study has highlighted the potential public health effect of addressing job strain factors in the workplace,” write the authors.
Mental health challenges are one of the biggest reasons why people are absent from work in high-income countries. Because of this, scholars and policymakers have been increasingly interested in the interaction between job characteristics and mental health.
The authors cite Karasek’s job demands-control model which suggests that high job demands and low job control (i.e., unable to make decisions about one’s work) lead to high job strain and may result in health problems. Cross-sectional and longitudinal studies have found an association between job strain and poorer mental health, providing support for Karasek’s model. However, the authors note that these studies have not been able to rule out reverse causation (e.g., being diagnosed with a mental health disorder may lead to having a less desirable job) or confounding factors (e.g., a third variable such as socioeconomic status is driving both job strain and mental health challenges).
Therefore, the authors sought to examine whether there is a causal relationship between high job demands, low job control, and high job strain with poor mental health. The researchers used data from the UK National Child Development Study, which included people born in the UK in 1958. The present study analyzed data from 6060 individuals who participated in a self-report survey at age 45 and had follow up data at age 50. In addition to measuring job strain and mental health, the researchers also assessed many possible confounding variables including marital status, education level, social position, occupational class, psychiatric history, stressful life events, and childhood intelligence.
After controlling for confounding factors, results show that high job demands, low job control, and high job strain at age 45 are significantly associated with developing a “common mental disorder” by age 50. The researchers estimate that “14% of new cases of common mental disorder could have been prevented through the elimination of high job strain.”
“The present study has analyzed life-course data to show that job demands, control, and strain have a prospective effect on risk of future onset of common mental disorder independent of lifetime psychiatric history and other potential confounding variables across the lifespan,” the authors summarize.
Although previous studies identified an association between job strain and mental health challenges, this study is the first to suggest a causal link, providing stronger evidence for Karasek’s job demands-control model.
This study has significant public health implications as one survey found that 1/3 of men with poor mental health attribute it to their jobs. Another study found that a stressful job may be worse for a person’s mental health than being unemployed. Therefore, these findings may be used as an argument for companies to reduce job strain on their employees in order to decrease the likelihood that their employees experience mental health issues.
Harvey, S. B., Sellahewa, D. A., Wang, M. J., Milligan-Saville, J., Bryan, B. T., Henderson, M., … Mykletun, A. (2018). The role of job strain in understanding midlife common mental disorder: A national birth cohort study. The Lancet Psychiatry. Advance online publication. http://dx.doi.org/10.1016/S2215-0366(18)30137-8 (Link)