Four groups were formed to test the hypothesis that participation in SAAF would moderate the association between youths’ 5HTTLPR status and increases over time in their risk behavior: (a) youth in the SAAF condition at genetic risk (n = 98), (b) youth in the SAAF condition without genetic risk (n = 146), (c) youth in the control condition at genetic risk (n = 73), and (d) youth in the control condition without genetic risk (n = 102). A one-way analysis of variance was used to determine the four groups’ pretest equivalence on the demographic and study variables, and chi-square tests were used to determine group equivalence on youth gender and maternal marital status. No equivalence comparison was significant. Pretest levels of the risk behavior index were controlled in the following analyses; this is standard practice because it allows hypothesized group differences in changes across time in outcome variables to be tested.
