La Follette School professor Jason Fletcher examined answers to survey questions asked by the National Longitudinal Study of Adolescent Health and correlated the answers to molecular DNA information the study also collects. "This large national survey explores the influences of individual attributes and environmental factors in determining health and health-related behaviors," says Fletcher, who published his findings in May in the journal Biodemography and Social Biology.
Wave 3 of the study's data collection covered the months before and after the terrorist attack of September 11, 2001. It included several measures of the mental health of the study participants, who were 18 to 26 years old when surveyed in 2001-02. "The study allows the use of a measure of an external stress that is objective rather than self-reported," Fletcher says.
Almost 60 percent of the sample was interviewed after 9/11, Fletcher says. "They had higher rates of reported depressive symptoms, especially reports of sadness. Participants with a particular gene appear to be at an increased risk for sadness. Others with a different genetic variant reported less of an increase in sadness, which suggests their genetic makeup protects them."
Another group with a particular genotype recovered from the sadness more slowly than those without, Fletcher adds.
"Overall, the evidence suggests that genetic endowments are an important source of variation in response to a stressful event in producing some depressive symptoms in young adults," Fletcher says.