Screening tests are medical tests carried out on presumably healthy people to identify an existing illness or pre-disease condition. They comprise a sub-category of health protective behaviours, sometimes labelled detection behaviour or secondary prevention. Screening is advocated as a cost-effective means of identifying individuals at a very early, pre-symptomatic stage of a disease when treatment is more effective and less costly. Identifying people at risk for disease enables health services to target those most likely to benefit from early intervention (see ‘Screening in healthcare’).

Psychologically, screening is different from other health behaviours. In contrast to ‘true’ preventive behaviours (e.g. exercising) that reduce the likelihood of future disease and provide a sense of safety, screening behaviours detect the presence of a serious illness and can be frightening. For this reason, conclusions gained from studying the former might not apply to screening behaviours. Despite these observations, there is still no specific theoretical framework for screening behaviour.

Four dimensions of screening have meaningful psychological implications:

1. Screening for disease versus risk factors. Detecting a risk factor for an illness (e.g. high cholesterol levels) is likely to be less fear-provoking than disease detection, since a positive test indicates only an increased chance of future harm. However, the recent completion of the sequencing of the human genome has brought predictive genetic testing to learn about one's risk to develop many common medical conditions (cancers, diabetes) later in life, for which there is little, or no prevention. Screening for such risk factors raises concerns about possible adverse social and psychological impacts of knowing one's risks, and is one of the major challenges facing health psychology in the twenty-first century.

2. […]