In examining concomitant alcohol and tobacco use, the omnibus GLM analysis revealed between-group differences in ImpSS scores (F(3, 2729) = 84.31, p < .001, partial ε2 = .087). Post hoc analyses indicated that two sets of significant differences existed: users of both alcohol and tobacco (12.43 ± 4.033) were more impulsive than users of only alcohol (10.88 ± 4.220), and all other groups had higher ImpSS scores than nonusers (8.96 ± 4.429; ps < .01). Users of alcohol only were not significantly different from users of tobacco only (11.14 ± 4.534; p = .825). Also, users of both did not significantly differ on ImpSS score from users of tobacco only (p = .062). These outcomes are summarized in Figure 2.
