Workplaces that reduce job strain could prevent up to 14 percent of new cases of common mental illness from occurring, according to new research led by the Black Dog Institute.
Published today in the Lancet Psychiatry, the results confirm that high job strain is associated with an increased risk of developing common mental disorders such as depression and anxiety amongst middle-aged workers.
Job strain is a term used to describe the combination of high work pace, intensity, and conflicting demands, coupled with low control or decision-making capacity.
"Mental illness is the leading cause of sickness absence and long-term work incapacity in Australia, equating to $11 billion lost to Australian businesses each year," said lead author Associate Professor Samuel Harvey from the Black Dog Institute.
"Our modelling used detailed data collected over 50 years to examine the various ways in which particular work conditions may impact an employee's mental health.
"These findings serve as a wake-up call for the role workplace initiatives should play in our efforts to curb the rising costs of mental disorders.
"It's important to remember that for most people, being in work is a good thing for their mental health. But this research provides strong evidence that organisations can improve employee wellbeing by modifying their workplaces to make them more mentally healthy."
The international research team analysed health data from the UK National Child Development Study, a large British cohort study.
Examining 6870 participants, they investigated whether people experiencing job strain at age 45 were at an increased risk of developing mental illness by age 50.
To determine levels of job strain, participants completed questionnaires at age 45 testing for factors including decision authority (the ability to make decisions about work), skill discretion (the opportunity to use skills during work) and questions about job pace, intensity and conflicting demands.
The researchers also accounted for non-workplace factors including divorce, financial problems, housing instability, and other stressful life events like death or illness. The models developed in this study controlled for individual workers' temperament and personality, their IQ, level of education, prior mental health problems and a range of other factors from across their early lives.
At age 50, participants completed the Malaise Inventory questionnaire, a psychological scale used in health surveys to indicate symptoms of common mental illness.
The final modelling suggests that those experiencing higher job demands, lower job control and higher job strain were at greater odds of developing mental illness by age 50, regardless of sex or occupational class.
"Our research attempted to account for the possible reasons an individual's work conditions could impact their mental health - and this modelling is the most complete ever published," said Associate Professor Harvey.
"The results indicate that if we were able to eliminate job strain situations in the workplace, up to 14 percent of cases of common mental illness could be avoided.
"Workplaces can adopt a range of measures to reduce job strain, and finding ways to increase workers' perceived control of their work is often a good practical first step. This can be achieved through initiatives that involve workers in as many decisions as possible."
The research was a collaboration between the Black Dog Institute, UNSW Sydney, King's College London, The Harvard TH Chan School of Public Health, NHS Foundation Trust, Norwegian Institute of Public Health, the Nordland Hospital Trust (Norway) and the Arctic University of Norway.
It is part of a program of research focused on workplace mental health that is funded by the icare foundation and the Mental Health Branch of NSW Health.
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Case studies and interviews available on request. The full research article can be accessed at http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(18)30137-8/fulltext