Regarding alcohol problems, although the overall time by impulsivity trajectory group interaction suggested a nonsignificant statistical trend [F(12, 477) = 1.58, p < 0.10], further contrast analyses suggested that Class 3, compared to all other impulsivity classes, displayed the steepest decreases in alcohol problems from ages 18 to 25 [F(1, 477) = 5.17, p < 0.05; see Fig. 2]. Further, cross-sectional analyses suggested that Class 3, compared to Class 1, was significantly higher in alcohol problems at age 18 (p < 0.05) but not significantly different from classes 2, 4, or 5. At age 25, Class 3 was significantly lower in alcohol problems compared to Class 4 (p < 0.05) and Class 5 (p < 0.05) but not classes 1 or 2. Class 3 did not differ significantly from the other impulsivity classes in alcohol problems at either age 29 or 35 (see Fig. 2).
