Familial context of genetic testing for cancer susceptibility: Moderating effect of siblings' test results on psychological distress one to two weeksafter BRCA1 mutation testing

Objectives. To determine whether psychological distress differs among indiv iduals tested for a BRCA1 mutation and is moderated by the pattern of their siblings' test results. Materials and Methods. Participants in this study are members of a large ki ndred identified with a BRCA1 mutation. Subjects included 87 males and 125 females who completed a baseline interview, were tested for a BRCA1 gene mu tation, received their results in person from a genetic counselor, complete d a follow-up inter-view 1-2 weeks after the receipt of their test results, and had complete data on all variables used in the analysis. The main outc ome of the study was psychological distress as measured by the Impact of Ev ent Scale during the 1-2 week follow-up interview. Data were analyzed based on multiple regression. Results. Male carriers, relative to noncarriers, experienced significantly more distress if they were the first tested than when all of their tested s iblings were already known to be negative. Noncarrier males whose siblings all tested positive also encountered significant test-related distress. The largest adverse psychological consequences for female carriers, relative t o noncarriers, were for those who were tested first and those whose tested siblings were noncarriers. Conclusions. The familial context in which genetic testing is conducted may be important for understanding how individuals react to their own test res ults.