No microscope can see it and no assay can detect it, but stress has been linked with cancer, infertility and immune-suppression. Worried? Don
’
t be
—
you
’
ll only make it worse.
By Bianca Nogrady
Stress is an inevitable part of modern life. Unfortunately, it comes with a hefty price tag. The National Heart Foundation now ranks stress equally with smoking, dyslipidaemia and hypertension as a risk factor for coronary heart disease. This represents a huge change in attitudes, according to the foundation’s clinical director, Professor Andrew Tonkin.
“Where the sands have shifted is, from thinking about the relationship between acute stressful events and acute cardiac events, to appreciating the relationship between chronic psychosocial factors and cardiovascular disease,” Professor Tonkin says.
Although ‘stress’ is an imprecise term, the NHF says it is commonly used to describe a range of variables, from conditions such as depression, anxiety and panic disorders to a person’s work and life circumstances.
Coronary heart disease
Studies have established a strong and consistent link between depression and CHD in men and women of all ages and nationalities. The more severe the depression, the greater the risk of CHD and the bleaker its prognosis. Stress resulting from social isolation and lack of quality social support also has been found to more than double the risk of CHD.
So clear is the relationship that the National Heart Foundation issued a position statement saying identified psychosocial risk factors should be taken into account in individual CHD risk assessment and management and that this has implications for public health policy and research.1
Gastrointestinal system
When it comes to the effect of stress on the GI system, most people have probably experienced abdominal pain before a job interview or unexplained chronic diarrhoea during a stressful period of life.
“Everybody knows that soldiers on the battlefield get gut ache and diarrhoea because they’re frightened,” says Sydney gastroenterologist Dr Katie Ellard, secretary of the Gastroenterological Society of Australia. The HSC exam period also leads to a spike in gastroenterology consultations, she says. “It’s a good illustration of what a quick and direct effect the brain and emotions have on your gut.”
The association between psychosocial factors and irritable bowel syndrome is particularly strong. One study found more than half of patients with severe IBS also had depression, and there is good evidence sexual abuse in childhood increases the incidence of the condition, Dr Ellard says. But the greatest proof is in the cure — psychotherapies such as hypnotherapy and cognitive behavioural therapy are as effective as conventional pharmacotherapy or dietary changes in treating IBS.
The immune system
The effect of stress on the immune system is so well established this field of study has even been given its own name: psychoneuroimmunology. US researchers found lonely college students and people caring for a spouse with Alzheimer’s disease had a reduced immune response to vaccinations against hepatitis B and influenza respectively.2 Another recent study found a half-hour-long argument between husband and wife delayed wound healing by more than a day.3
“In individuals who produced delayed, weaker and shorter-lived immune responses to vaccines, it is reasonable to assume these same individuals would also be slower to develop immune responses to other pathogens,” wrote the authors of a review.4“There is now good evidence (in animal and human studies) that the magnitude of stress-associated immune dysregulation is large enough to have health implications.”
Auto-immune disease
The effect of stress on auto-immune disease is less clear cut. According to one review, there is ample anecdotal evidence that stress exacerbates auto-immune conditions, but there is also evidence associating it with remission of these conditions.5 One study of patients with asthma found no change in lung function during a stressful exam period.6 However, another study found women with rheumatoid arthritis experienced a greater increase in clinical symptoms during a period of stress if they received less support from their spouse, compared with those who were better supported.7
Cancer
The evidence for a link between stress and cancer is even less clear, despite the popular view that the two are intrinsically linked, says psychiatrist Dr Jane Turner, a senior lecturer at the University of Queensland.
“There’s a pervasive belief in the community that stress causes cancer and that stress will exacerbate cancer, but it’s not supported by the evidence,” Dr Turner says. “There have been isolated studies that have shown some links, but it is certainly not a major consistent factor that has been demonstrated in the literature.”
A recent Danish study raised the possibility that chronic stress could actually reduce risk of breast cancer, particularly among women receiving hormone therapy.8The researchers suggested stress might impair oestrogen synthesis, lowering endogenous concentrations of oestrogen.
Patients often try to link their cancer to stress because it gives them some sense of control over an uncertain disease, Dr Turner says. “Patients put pressure on themselves to avoid stress because they think that will help, but they also get pressure from other people to be positive,” she says. “However, the worry I have is you can’t eliminate stress from your life [and] the other problem is that, if there is a further problem with the disease, is it somehow the person’s fault because they didn’t try hard enough?”
Pregnancy
Pregnant women are another group who can find themselves under pressure to relax because of concerns that stress can harm the baby, with evidence suggesting stress in pregnancy can lead to increased risk of depression and type 1 diabetes in offspring.
Adverse effects of stress in pregnancy are likely to be mediated by the stress hormone, cortisol, says Associate Professor Anne Buist, a psychiatrist at Melbourne’s Austin Health. The Avon cohort study measured cortisol levels in 10-year-old children and found they were particularly high when the mothers had experienced greater anxiety in late pregnancy, says Professor Buist who is involved in a large Australian study examining risk factors for antenatal and postnatal stress with a view to developing a screening program.
Identifying stress
With the issue of screening comes the question of how to identify stress in patients, and part of the problem is first defining stress, says Dr Grant Blashki, a GP and senior research fellow at Monash University’s department of general practice.
“The first thing to recognise is that the term stress means a lot of different things to a lot of different people,”Dr Blashki says. Some patients use the term stress as a euphemism for depression or anxiety, and the challenge for GPs is to recognise when stress is tipping over into what could be considered a psychiatric diagnosis, he says. The situation is made more complex by the fact that stress rarely presents in an obvious fashion.
“An enormous amount of psychological distress comes in with physical symptoms in the first instance,” Dr Blashki says. Although public awareness campaigns about depression have increased the number of patients presenting with self-identified depression, most patients still come in with various vague physical symptoms such as tiredness, inability to cope, headaches, neck pain or difficulty sleeping, he says. The more symptoms a patient has, the more likely he considers depression and anxiety to be the root cause.
Talking about stress with patients is not always easy, Dr Blashki says. “Some people won’t take kindly to being told their physical symptoms are because [they’re] psychologically distressed.”
The authors of one review suggested patients could be helped to make the connection between the timing of their symptoms and psychological events.9
“This simply involves asking the person in detail about life events, work, family events and so forth, without identifying these as stressors,” they wrote. “Often patients can nominate particular events or concerns which can be matched temporally with problems in health or symptom control, even though they have never made the link themselves.”
Once the connection has been made, the next step is to manage the stress. Although stress management is a rapidly growing field of expertise, not all of the treatments on offer are evidence-based, Dr Blashki says.
“As GPs, we fundamentally need to rely on scientific evidence,” he says. “There may be all sorts of things out there, but we have an obligation to the patient to be clear about what’s based on science and what’s anecdotal and they can make up their own mind.”For example, meditation is increasingly popular with patients looking for non-medical ways of managing stress. Although there is growing evidence for its benefits, particularly in preventing depression relapse, Dr Blashki says the technique still needs to be in the “new controversial”bag.
Professor Chris Tennant, professor of psychiatry at the University of Sydney, says lifestyle prescriptions can help people cope with stress. “You can’t lead a life without stress so … you have to learn to handle better the impact of stress on the body.” Exercise, meditation, Tai Chi and yoga are all “general background alleviators” of stress, he says, but ultimately the best approach is to reduce the stress itself.
“You can’t avoid stressful events — shit happens … but some you can reduce by sensible choices.”
References
1. Medical Journal of Australia2003; 178:272-76.
2. Annals of the New York
Academy of Sciences 1998; 840:649-55.
3. Archives of General
Psychiatry 2005; 62:1377-84.
4. TRENDS in Immunology2003; 24:444-48.
5. Journal of Consulting and
Clinical Psychology 2002; 70:537-47.
6. Brain, Behaviour and
Immunity 1996; 10:164-81.
7. Arthritis Care and Research1998; 11:271-79.
8. BMJ 2005; 331:548-50.
9. MJA Practice Essentials 1998; www.mja.com.au/public/mentalhealth/articles/turner/turner.html.
HOW DOES STRESS AFFECT THE BODY?
Chronic stress leads to overproduction of glucocorticoid hormones, such as cortisol, and catecholamines such as epinephrine and norepinephrine. This interferes with regulation of cytokine-producing immune cells and alters gene expression for various cytokines, with the end result being dysregulation of immune function.
Researchers from the Garvan Institute in Melbourne also recently discovered what they believe to be a hormone at least partly responsible for the effects of stress on the immune system.1 Neuropeptide Y normally regulates T-cell activity but stress causes larger than normal amounts of the hormone to be released, effectively suppressing the T-cell response and therefore lowering immunity.
1. Journal of Experimental Medicine 2005; 202:1-13.
MANAGING STRESS
Various techniques can be applied in general practice to help patients manage stress:
– Supportive counselling -- components include reassurance, explanation, guidance, suggestion, encouragement and changing the patient's environment
– Progressive muscle relaxation
– Slow breathing exercises -- to help patients understand the link between effects of hyperventilation and their physical symptoms and provide them with a way to prevent hyperventilation in stressful situations
– Sleep-wake cycle management -- educating patients about the body clock and emphasising the importance of activity in the day and avoidance of over-stimulation before sleep
– Activity planning -- a structured approach for engaging those patients who have withdrawn from their usual activities
Australian Family Physician 2003; 32:715-21.
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