Even minor mental health issues may raise the risk of death, a new U.K. study finds. Among disease-free, healthy adults in the study, the more signs of psychological distress that people had, the higher the death rates they experienced — even at low levels of distress, the study authors say, and even after accounting for a large number of health conditions and health behaviors that might explain the link.
In the past, other studies have also found a link between mental health and mortality risk. But to date it’s been hard to tell whether psychological distress is really contributing to poor physical health, or whether, instead, some people who are already sick — and so at higher risk of death to begin with — simply become upset or anxious because they don’t feel well physically.
This latest study attempts to separate cause from effect. For the study, released this week in the journal BMJ (formerly the British Medical Journal), researchers analyzed several years of data from a large, general population survey in England. While it’s never truly possible in this type of study to say that one thing definitely causes another, the analysis only included adults without known heart disease or cancer at the beginning of the study — a restriction meant to eliminate people whose poor health might be affecting their mood. It also adjusted statistically for a number of other things that might be related both to death risk and to mental health, including age, sex, social class, diabetes status, cigarette consumption, and body mass index (a measure of weight relative to height).
In one final analysis, the researchers then looked exclusively at the relationship between mental health and deaths that occurred at least five years after psychological distress had been measured — yet another technique to limit the possibility that any link between mental health and mortality is the result of people becoming distressed once they’re already at death’s door.
In all the analyses, people with greater signs of psychological distress had higher risk of death, with even very mild symptoms translating into some excess mortality risk. The more severe the symptoms, the higher the death risk.
Mental distress itself was measured with a simple 12-point quiz known as the General Health Questionnaire. It asks people questions such as, “Have you recently lost much sleep over worry?” or “Have you recently been able to concentrate on whatever you are doing?”
The researchers found a similar dose-response relationship between psychological distress and deaths from cardiovascular disease that they saw between psychological distress and mortality from any cause. The risk of death from cancer only, in contrast, was elevated only among people with distress scores high enough that they could be considered to have a clinical condition.
The researchers note that chronic stress can lead to hormonal dysregulation and increased levels of inflammatory markers. They speculate that those effects might be responsible in part for the link between mental health problems and mortality.
Since the link is present even among people with only low levels of psychological distress, the findings may apply to large swaths of the population. But the implications of that are not clear, the study authors say. As they write in their BMJ paper:
While the association between psychological distress and mortality has attracted a great deal of attention, little evidence indicates favourable effects, in terms of mortality, with treatment.
Perhaps, then, we should make an effort not to treat the symptoms of mental distress, but rather to prevent people from getting distressed in the first place? In an accompanying editorial also published this week in BMJ, University of Bristol psychiatry professor Glyn Lewis considers the possibility.
“Obvious sources of stress such as workplace stress could be modified,” he writes. “It is also worth considering how societal stresses related to inequalities and socioeconomic status might contribute to the incidence of cardiovascular disease.”
Still, we cannot eliminate all possible sources of stress from our lives and, given that many people enjoy an occasional challenge too, Lewis warns, attempts to avoid all stressors could backfire and even “lead to more anxiety in the long run.”
“A more useful approach could be to change the psychological interpretation of stressors” — to learn to cope better, in other words — “because this might reduce their biological impact.”
That’s easier said than done, of course. With such a disturbing finding, only one thing is certain: it doesn’t help to worry about it too much.