A recent study published in the 2012 July issue of the British Medical Journal is probably the largest so far to show that a dose-response association exists between psychological distress and major causes of mortality across the full range of distress.
Psychological stress has been linked to the development and progression of several common human diseases including allergy, cancer, cardiovascular and autoimmune disorders (see Clinical Aspects, News and Features and Faces sections, and Evolving Concepts category of this website).
In addition, an increasing body of evidence indicates an association between symptoms of depression and anxiety (often referred to as psychological distress) and mortality from various major causes.
In the British Medical Journal study, Tom Russ and colleagues from the University of Edinburgh and University College London, UK analyzed data from over 68,000 adults aged 35 years and over who took part in the Health Survey for England from 1994 to 2004.
The study is the first to use an individual participant meta-analysis methodology of 10 large prospective cohort studies to examine the association between a psychological variable and mortality. Psychological distress was measured using the 12 item version of the General Health Questionnaire (GHQ-12), a widely used measure of distress in population studies.
The authors found a significant association, across the full range of severity, between psychological distress and all cause mortality, and this association remained after taking into account other factors such as weight, exercise, smoking, alcohol consumption and diabetes.
Even sub-clinically symptomatic patients (GHQ-12 scores 1-3) were at a 29% increased risk of cardiovascular disease death or death from external causes. Cancer death was not associated with low levels of psychological distress; however, psychological distress in highly symptomatic patients (GHQ-12 scores 6-12) was associated with a 41% increased risk of cancer death.
In a press release, Dr Tom Russ, the lead author, and Dr David Batty, the senior author, commented that “even people with low distress scores were at an increased risk of death. Currently these people—a quarter of the adult population—are unlikely to come to the attention of mental health services due to these symptoms and may not be receiving treatment”, and “If you score one, two or three on this scale you may be suffering some form of social dysfunction or loss of confidence but your GP will not diagnose you with psychological distress”.
According to the authors, this “should prompt research into whether treatment of these very common, minor symptoms can modify this increased risk of death.”