Predictive testing for Huntington's disease has potential benefits for the psychological health of persons who receive results that indicate either an increase or a decrease in the risk of inheriting the gene for the disease.

Prior to the implementation of predictive-testing programs for Huntington disease (HD), significant concern was raised concerning the likelihood of catastrophic events (CEs), particularly in those persons receiving an increased-risk result. We have investigated the frequency of CEs-that is, suicide, suicide attempt, and psychiatric hospitalization-after an HD predictive-testing result, through questionnaires sent to predictive-testing centers worldwide. A total of 44 persons (0.97%) in a cohort of 4,527 test participants had a CE: 5 successful suicides, 21 suicide attempts, and 18 hospitalizations for psychiatric reasons. All persons committing suicide had signs of HD, whereas 11 (52.4%) of 21 persons attempting suicide and 8 (44.4%) of 18 who had a psychiatric hospitalization were symptomatic. A total of 11 (84.6%) of 13 asymptomatic persons who experienced a CE during the first year after HD predictive testing received an increased-risk result. Factors associated with an increased risk of a CE included (a) a psychiatric history

By January 1, 1991, a total of 388 persons had enrolled in the Canadian collaborative study of predictive testing for Huntington disease (HD). Of these participants, 105 persons have been given a decreased risk result. Contrary to expectations, approximately 10% of persons with a decreased risk result have had psychological difficulties coping with their new status. Here, we describe the individual responses of 6 such persons and experimental themes emerging after following these persons for up to 2 years. Individuals who are more likely to suffer an adverse reaction to a decreased risk result include those persons who have made irreversible decisions based on the belief they would develop HD or those who had unrealistic overoptimistic expectations of the positive effects of a decreased risk result. In contrast to those receiving an increased risk result, the most vulnerable time for persons receiving a decreased risk result is between 2 and 12 months after learning the outcome. The need for assessment and counselling of participants in predictive testing programs, even when there is a decreased risk result, is emphasized.

Predictive testing for Huntington disease (HD) has been offered in some parts of Canada for nearly 5 years. Candidates who were expected to have a significant likelihood for psychological problems were those who received an increased risk for developing HD. Sixty-six persons have now received such an increased risk result. In this manuscript we describe in detail the experience of 4 such persons who were chosen to illustrate recurrent and common themes which have emerged during counselling, and to highlight the strategies of coping with this information. Themes include difficulties communicating about HD, defensive postures adopted in preparing for testing, ramifications of testing for the whole family, and the impact of being at high risk on the candidates' perception of the future. One candidate has had testing postponed due to active suicidal risk. Only a few candidates have expressed regret at taking the test and no person receiving an increased risk result has made a suicide attempt or required hospitalization. After receiving results, symptoms of depression and anxiety are most common in the first 2 months, but over 1 year, candidates, in general, have less depression but live with a heightened perception of the present. The potential risk of premature diagnosis of HD in an individual with an increased risk results is highlighted. The significant ramifications of testing for the relative are shown. The importance of communication as a means of establishing a social support network, as well as the hazards of open communication, are discussed. Longitudinal evaluation will provide much needed data on the long-term effects of living at increased risk for HD.