Sequence

C (n = 19)^{a}

D (n = 24)^{a}

E (N = 17)^{a}

F (N = 20)^{b}

*Pvalue


Age started (mean ± SD)

16.15 ± 4.34

17.04 ± 4.92

17 ± 3.77

12.05 ± 3.94

< 0.0001

 C (sequencing C): tobaccoopiumMA; D (sequencing D), tobaccoopiumheroinMA; E (sequencing E): tobaccoalcoholopiumheroinMA; and F (sequencing F), tobaccoalcoholcannabisopiumheroinMA.
 MA methamphetamine
 Dissimilar values (superscripts a and b) of each row are significantly different.
 *Values were analyzed by oneway analysis of variance (ANOVA); values are mean ± SD