Screening could seriously damage your healthBMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7080.533 (Published 22 February 1997) Cite this as: BMJ 1997;314:533
Decisions to screen must take account of the social and psychological costs
- a Health Services Research Unit, Department of Public Health and Primary Care, University of Oxford, Oxford OX2 6HE
The costs and benefits of screening programmes are generating more than their usual share of interest. Last week the NHS Executive's new national screening committee held a press conference at the Royal College of Surgeons and declared that the costs of prostate cancer screening-in terms of impotence, incontinence, postoperative mortality, and psychological disturbance-outweighed any possible benefits. This statement was made possible because of two systematic reviews commissioned by the Health Technology Assessment programme.1 2 Many more systematic reviews of screening programmes are due to be reported soon, so the debate on screening will continue to run.
The decision about prostate cancer screening was relatively easy because there is no reliable evidence that early treatment improves outcome and the operative morbidity is unacceptable. But for some programmes due to be reported on soon the decisions may be more difficult; the benefits of a small increase in life expectancy or reduction in disability for a small number of people will need to be balanced against a range of harmful psychological effects. People receiving false positive results have been shown in three different screening programmes (for congenital hypothyroidism,3 breast cancer,4 and Down's syndrome5) to suffer high levels of anxiety which do not resolve immediately when subsequent testing shows no signs of disease.
People found in workplace screening programmes to be hypertensive have increased sickness absence, increased anxiety, and reduced self perceived health status, regardless of whether their hypertension warranted treatment.6 7 Several studies on the effectiveness of cholesterol testing have shown a paradoxical effect: a reduction in deaths from heart disease but a small increase in total mortality.8 It has been suggested that men who know that they are at increased risk of dying of heart disease may be more inclined to take other risks. Some of these adverse psychological effects probably also have an impact on the family and friends of the individual who has been screened.
Some of this literature on adverse effects is contradictory and many potential deleterious effects have yet to be researched. One of these is the “certificate of health effect.” 9 This suggests that people who have received a negative result on screening may be more resistant to advice on healthy lifestyles. For example, people who screen negative for cancer may feel safe continuing smoking, and those with low serum cholesterol eating their unhealthy diets. Screening programmes may also imply that good health can be maintained by regular visits to the doctor for check ups and that individual behaviour is less important.
Screening is a relative newcomer to healthcare provision and it is likely to have had some impact on the way people think about health and disease. Public misconception about the purpose of screening programmes has been demonstrated in Australia,10 and a reduced sense of personal control over health has been shown to be associated with poorer self rated health, more episodes of illness, and less self initiated preventive care.11
Screening programmes affect a large number of people relative to the number who benefit. A small adverse effect of screening on quality of life, health promoting behaviour, or individuals' capacity to care for themselves could have an impact on the public health which outweighs any health gain to be achieved by screening.
Calls to establish new screening programmes are usually based on evidence of benefits to people who are found to have the disease. Until we know the full impact of these programmes on the health and wellbeing of others it will be difficult to decide whether these programmes are good for the public's health. This is why the NHS Research and Development Programme has recently called for bids to undertake primary research into the effect of screening on self care and health related behaviour. This is conceptually different from what has been done before because it is trying to measure broad sociological effects of screening in contrast to individual psychological effects. These effects are intrinsically difficult to research, but the research community does need to rise to the challenge. We must know the social and psychological costs of screening before deciding whether individual screening programmes should or should not be provided.