In their study on the impact of presymptomatic genetic testing for neurogenetic disorders, Smith et al1 found that 13 (33%) of 39 individuals reported elevated anxiety levels during follow-up, from which they conclude that anxiety may persist in some persons with positive or negative test results. However, a closer look at their data reveals that these individuals had elevated anxiety scores at different follow-up assessments, since 10 (26%) of 38 individuals reported elevated anxiety levels immediately after testing, and 5 (21%) of 24 at 1-year and 7 (39%) of 18 at 2-year follow-up. Although these percentages of patients with elevated anxiety levels are substantial, they do not provide evidence for a long-term impact of genetic testing. The response rates at the follow-up assessments were 76%, 48%, and 36%, and it is not reported whether these were representative samples of the 50 participants who entered the study.
Janssens ACJW. Impact of Presymptomatic Genetic Testing for Hereditary Ataxia and Neuromuscular Disorders: Where is the Evidence?. Arch Neurol. 2005;62(1):164. doi:10.1001/archneur.62.1.164-a