Stress at work is a risk factor for depression

People with high-stress jobs have twice the risk of developing serious depression or anxiety compared with others in less stressful occupations, The Independent reported. The link between rising rates of depression and rates of work stress means that “one in 20 cases of depression or anxiety annually is attributable to high stress at work”, it stated on August 2 2007.

Highly stressed jobs include head chefs and construction workers, the paper reports, and least stressful jobs include looking after children at home, “where there are no deadlines to meet, greater flexibility and no fear of public failure”. The researchers explain that “time pressure is the single most important cause of stress and of the illness to which it leads,” the newspaper said.

The research supports the intuitive link between stress at work and the mental health of young working adults.

Where did the story come from?

The research was carried out by Maria Melchior and colleagues at the Institute of Psychiatry, Kings College London. Other institutions in the US, France and New Zealand were also involved. It was supported by universities, research institutes or research councils in all of these countries and was published in the journal,_ Psychological Medicine._

What kind of scientific study was this?

This is an analysis of data from a cohort study carried out in Dunedin, New Zealand. In this study 1037 babies (92% of the population) born between April 1972 and March 1973 were enrolled and there have been 11 follow-up visits. This study examined data from their visits at age 32 years. Of the original participants, 1,015 were still alive and 972 (96% of these) completed the assessment.

The participants were given a questionnaire that asked questions about the psychological and physical demands of their job, their freedom to make decisions at work, as well as the support that they receive at work from colleagues. 

During the same visit, the participants were assessed for any psychiatric disorders using a validated interview, by an interviewer who was unaware of the other scores. Participants were considered to have a new diagnosis of depression or anxiety disorder if they met the diagnostic criteria at the time of interview, and had no previous diagnosis or related medication or hospital treatment.

Mathematical methods were used to adjust for other potential contributing factors such as socio-economic status or negative attitudes of the participant when completing the interviews.

What were the results of the study?

The results showed that participants exposed to high psychological job demands had twice the risk for major depression disorder or generalised anxiety disorder compared with those with low job demands.

What interpretations did the researchers draw from these results?

The researchers concluded that work stress appears to lead to depression and anxiety in previously healthy volunteers, and that reducing work stress, or helping workers cope with stress, could prevent the occurrence of clinically significant depression.

What does the NHS Knowledge Service make of this study?

This well conducted study provides long-term data without the problems that can occur due to an unrepresentative selection of participants, as everyone born in a particular year was enrolled. It appears to confirm that work stress is a factor in the development of depression or anxiety. There are a few limitations, which the authors acknowledge:

• The questionnaires about work stress and the interviews about mental health were conducted at the same time. Although the researchers conducting each separate interview did not know the score from the other, how an individual responded to one set of questions may have been affected by their responses to the other. Depression may have influenced the participants’ rating of their work characteristics or make them less likely to recall details accurately.
• Work patterns or culture may be subtly different in a New Zealand population compared with other countries; this may limit how the results of this study can be applied across the world.

The positive aspects of an observational study of this sort are the gradient of risk demonstrated. Increasing risk was shown in those people with the most psychologically demanding jobs. This effect and the adjustments made by the researchers for other influences such as socio-economic status, allow more confidence that this is not merely a chance finding.