Testing for Huntington's disease with support for all parties.
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Biomedical subjects
Publications and source records attributed to A Tibben.
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This study assessed the 6-month follow-up effects of presymptomatic DNA testing for Huntington's disease (HD) in 73 individuals at 50% prior risk who were identified either as carriers of the HD gene (N = 29) or as noncarriers (N = 44). The subject's knowledge of being a gene carrier was expected to induce intrusive emotions, denial-avoidance behavior, and pessimistic expectancies of the future and adjustment problems. The Impact of Event Scale, the Beck Hopelessness Scale, and the General Health Questionnaire were used as standard measures of psychological distress. At the disclosure of the test results, carriers had a strong increase in pessimistic expectations but showed a decline to baseline levels 6 months later. Noncarriers reported a steep decline in hopelessness compared with their pretest conditions but had increased scores after 6 months. Six months after the disclosure of the test results, both gene carriers and noncarriers reported a significant decrease in unwanted intrusive thoughts about HD. Carriers showed a slight increase in denial-avoidance behavior, whereas noncarriers showed a clear decrease. Our observations might indicate that tested individuals found relief from the prior psychological distress and that they were able to acknowledge the impact of the test result on their future. An unresolved question is how the foreknowledge will affect carriers as they approach the impending onset of the disease. Longer observation periods (> 6 months after disclosure) are required to study changes of the impact of DNA test results over time.
OBJECTIVE: To compare the effects of predictive DNA testing on participants at risk for either Huntington disease (HD), or familial adenomatous polyposis (FAP), or hereditary breast and ovarian cancer (HBOC). METHOD: Psychological distress was measured with the Impact of Event Scale before testing and at 1 week and 6 months after the test result, in individuals at 50% risk for either HD (N = 25), FAP (N = 23), or HBOC (N = 10). RESULTS: A marginally significant trend was found indicating that carriers of the disease genes tended to show unchanged levels of distress during the study period whereas noncarriers showed the expected decrease. Men reported significantly less distress than women, and 1 week after the test result male noncarriers showed a sharp significant increase in the reported distress followed by a steady decline up to 6 months later. CONCLUSIONS: The course of distress over time reported by carriers and noncarriers of the three disease genes was similar, which leads one to conclude that the previous experience with predictive testing for Huntington Disease may be a useful paradigm. However, those formerly at risk for HD reported more distress than those at risk for FAP and HBOC. From our clinical experience we learned that individuals at risk for FAP and HBOC are more inclined to ward off the emotions involved. Additional qualitative studies should be undertaken to investigate this.