People completed questionnaires about their level of job strain at age 45 then, at age 50, a questionnaire commonly used to indicate signs of common mental illness.
Researchers also accounted for other stress-inducing factors including divorce, financial problems, housing instability, and bereavement or illness.
Results were then adjusted to rule out the effects of factors such as people's personalities, their IQ, level of education, previous mental health problems.
Double the risk if your job is 'high strain'
When compared with a control group, those with high job demands are 70
People whose job is classed as 'high strain' have more than double the risk – a 122 percent increase – of developing mental illness in their middle age.
The final results show people with higher job demands, lower job control and higher job strain are more likely to develop mental illness by age 50, regardless of their gender or type of job.
Mental illness the leading cause of time off work
Professor Harvey added: 'Mental illness is the leading cause of sickness absence and long-term work incapacity in Australia, equating to billion lost to Australian businesses each year.
'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.'
Past research shows stress linked to physical illness
Previous research has also shown that high levels of stress at work can increase the risk of heart attacks, and make people more likely to eat unhealthily and sleep and exercise less.
Stress can make people physically ill because it can stimulate white blood cells to react in the same way that illness does and cause the body to react as though it is fighting an infection when it is not.
Pictures: These Therapeutic Podcasts Will Help You De-Stress
We are thankful to Dr. Craig Porter (UTMB) for help in mitochondrial functional analysis studies.