In the DNHS, we found support for a significant additive interaction between the GRS and traumatic events that was associated with the frequency of cigarette smoking. As mentioned above, several previous studies have reported an interaction between a specific genetic variant and some aspects of trauma as a predictor of cigarette smoking.32, 35 Although genetic risk was related to an increase in the number of cigarettes smoked per day, the influence of the genetic risk variants for smoking was greater for individuals who had experienced trauma in their lifetimes than for individuals who had not. In this study, we expanded upon these results by examining the interaction between the experience of traumatic events and an aggregate measure of molecular genetic risk for cigarette smoking. The association between the GRS and cigarette smoking was stronger for individuals who had experienced more traumatic events.
