Psychological consequences of predictive genetic testing: a systematic review.

The aim of this systematic literature review is to describe the psychological consequences of predictive genetic testing. Five databases were searched for studies using standardised outcome measures and statistical comparison of groups. Studies were selected and coded by two independent researchers. From 899 abstracts, 15 papers, describing 11 data sets, met the selection criteria for the review. The studies were of predictive genetic testing for Huntington's disease, hereditary breast and ovarian cancer, familial adenomatous polyposis and spinocerebellar ataxia. One involved children; the rest were of adults. None of the 15 papers reported increased distress (general and situational distress, anxiety and depression) in carriers or non-carriers at any point during the 12 months after testing. Both carriers and non-carriers showed decreased distress after testing; this was greater and more rapid amongst non-carriers. Test result (ie being a carrier or non-carrier) was rarely predictive of distress more than one month after testing (predictive in two of 14 analyses). Pre-test emotional state was predictive of subsequent distress in 14 of 27 analyses. There is a lack of informative studies in this field. The studies reviewed suggest that those undergoing predictive genetic testing do not experience adverse psychological consequences. However, the studies are of self-selected populations who have agreed to participate in psychological studies and have been followed up for no more than three years. Most research has been of testing for Huntington's Disease and included follow-up of no more than one year. The results suggest that testing protocols should include a pre-test assessment of emotional state so that post-test counselling can be targeted at those more distressed before testing. None of the studies experimentally manipulated the amount or type of counselling provided. The relationship between counselling and emotional outcome is therefore unclear and awaits empirical study.