Patient accounts of diagnostic testing for familial hypercholesterolaemia: comparing responses to genetic and non-genetic testing methods.

BACKGROUND: Continuing developments in genetic testing technology together with research revealing gene-disease associations have brought closer the potential for genetic screening of populations. A major concern, as with any screening programme, is the response of the patient to the findings of screening, whether the outcome is positive or negative. Such concern is heightened for genetic testing, which it is feared may elicit stronger reactions than non-genetic testing. METHODS: This paper draws on thematic analysis of 113 semi-structured interviews with 39 patients being tested for familial hypercholesterolaemia (FH), an inherited predisposition to early-onset heart disease. It examines the impact of disease risk assessments based on both genetic and non-genetic information, or solely non-genetic information. RESULTS: The impact of diagnostic testing did not seem to vary according to whether or not genetic information was used. More generally, being given a positive or negative diagnosis of FH had minimal discernible impact on people's lives as they maintained the continuity of their beliefs and behaviour. CONCLUSIONS: The results suggest that concerns about the use of genetic testing in this context are unfounded, a conclusion that echoes findings from studies in this and other health contexts.

Why does genetic causal information alter perceived treatment effectiveness? An analogue study.

OBJECTIVES: When a health problem is perceived as having a genetic cause, this appears to increase the perceived effectiveness of pharmacological treatments and reduce perceived effectiveness of non-pharmacological treatments. Potential mediators of this effect include causal attributions, perceived severity, and perceived control over the health problem. This study aimed to use experimental methods to establish which beliefs mediate the effect of genetic causal information on perceived effectiveness of treatments. DESIGN: A 4(cause: environmental, family history, genetic test, family history & genetic test)×2(severity: higher or low) between-subjects design using vignettes about heart disease risk, obesity or depression. METHODS: A total of 647 adults, randomly assigned to read one of the experimental vignettes, were interviewed. Key outcomes were perceived effectiveness of medication and of non-pharmacological treatments. Potential mediators of perceived severity, perceived controllability, and causal attributions were also assessed. RESULTS: For heart disease risk, genetic causes reduced perceived effectiveness of non-pharmacological treatments (an effect mediated by causal attributions and perceived control) but did not influence perceived medication effectiveness. For obesity, neither severity nor cause influenced the perceived effectiveness of either treatment. For depression, genetic causes only increased perceived effectiveness of medication for more severe depression, an effect mediated by perceived control. CONCLUSIONS: The impact of genetic causal information on perceived effectiveness of treatments varies with type of health problem. When genetic causal information influences perceived treatment effectiveness, it does so by altering causal attributions and perceived controllability. However, these effects are small and unlikely to translate into clinically meaningful differences in health-enhancing behaviours.