Table 5. Characteristics of early-onset and later-onset substance use latent classes.

	Latent class 1 Early-onset (n = 243)	Latent class 2 Later-onset (n = 203)
	M ± SD or N (%)
Age at entry	21.1 ± 3.3	21.4 ± 3.1
Gender (female)	129 (53%)	119 (59%)
Substance use onset (age, years)
Alcohol	13.6 ± 1.9	16.9 ± 1.5
Tobacco	14.0 ± 1.8	18.3 ± 2.2
Cannabis	15.0 ± 1.9	18.7 ± 2.2
Amphetamine-type stimulant	17.0 ± 2.3	20.1 ± 2.0