Consistent with these findings, cross-sectional tests indicated that the developmentally limited impulsivity class (Class 3) exhibited significantly higher levels of alcohol QF at age 18 compared to Class 1 (p < 0.01) and Class 2 (p < 0.01) but was not significantly different in alcohol QF at this age compared to Classes 4 and 5 (see Fig. 2). However, at age 25, Class 3 was significantly lower in alcohol QF compared to Class 4 (p < 0.05) and Class 5 (p < 0.05) and was not significantly different in alcohol QF compared to Classes 1 and 2. Class 3 did not differ significantly from the other impulsivity classes in alcohol QF at either age 29 or 35 (see Fig. 2).
