Table 1.

Prevalence of SUD Subtypes

N = 56
N = 137
χ2(2)PValue*
N (%)N (%)N (%)
Baseline SUD 0 (0)7 (37)18 (13)19.2 <.001
Alcohol A/D0 (0)7 (37)15 (11)20.7 <.001
Marijuana A/D0 (0)4 (21)8 (6)11.7 .001
Hallucinogen A/D0 (0)4 (21)4 (3)17.9 <.001
Stimulant A/D0 (0)1 (5)2 (1)12.8 .2
Cocaine A/D0 (0)0 (0)2 (1)1.1 .6
Follow-up SUD 14 (25)14 (75)25 (18)19.5<.001
Alcohol A/D12 (21)13 (68)21 (15)20.5<.001
Marijuana A/D9 (16)8 (42)11 (8)13.6.001
Hallucinogen A/D4 (7)3 (16)5 (4)4.7.09
Stimulant A/D1 (2)1 (5)0 (0)5.8 .06
Cocaine A/D1 (2)3 (16)2 (1)8.2.02
Follow-up tobacco A/D19 (34)6 (32)22 (16)8.8.012
• * Logistic regression model using robust estimates of variance to account for familial associations between siblings.

• SUD subtypes are not mutually exclusive.

• Uncorrected P value reported because regression model would not converge due to cell with zero observations.