Psychological consequences of predictive genetic testing: a systematic review

The aim of this systematic literature review is to describe the psychologic al 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 adeno matous polyposis and spinocerebellar ataxia. One involved children; the res t were of adults. None of the 15 papers reported increased distress (genera l and situational distress, anxiety and depression) in carriers or non-carr iers at any point during the 12 months after testing. Both carriers and non -carriers showed decreased distress after testing; this was greater and mor e rapid amongst non-carriers. Test result (ie being a carrier or non-carrie r) was rarely predictive of distress more than one month after testing (pre dictive 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 st udies in this field. The studies reviewed suggest that those undergoing pre dictive genetic testing do not experience adverse psychological consequence s. 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 Disea se and included follow-up of no more than one year. The results suggest tha t testing protocols should include a pre-test assessment of emotional state so that post-test counselling can be targeted at those more distressed bef ore testing. None of the studies experimentally manipulated the amount or t ype of counselling provided. The relationship between counselling and emoti onal outcome is therefore unclear and awaits empirical study.