For alcohol QF, a significant time by impulsivity trajectory group interaction was found, F(12, 476) = 2.37, p < 0.01. Follow-up contrasts suggested that Class 3, versus all other impulsivity groups, made the steepest decreases in alcohol QF between the ages of 18 to 25 [F(1, 476) = 8.93, p < 0.01; see Fig. 2]. Further, Class 3, compared to Class 4, exhibited significantly sharper decreases across this timeframe [F(1, 476) = 4.81, p < 0.05; see Fig. 2]. Between the ages of 25 to 29, Class 4 and 5, compared to Class 3, made steeper decreases in alcohol QF [F(1, 476) = 6.25, p < 0.05], suggesting that Class 4 and 5 “developmentally lagged” in making reductions in alcohol QF compared to Class 3.
