Table 2.

Prevalence, odds ratio, and p values for offspring conduct disorder (CD) (three or more symptoms) as an unadjusted function of paternal drug-dependence (DD) or alcohol-dependence (AD) history

	Offspring CD
Variable	Prevalence %	OR [95% CI]	pa
Multifactorial model
1. HGHE-D
Hi-G and hi-E DD/AD groupb	21.3	2.27 [1.55, 3.30]***	.000
2. HGLE-D
Hi-G and low-E DD/AD groupb	14.7	1.44 [0.71, 2.92]	.32
3. MGLE-D
Mod-G and low-E DD/AD groupb	11.1	1.05 [0.49, 2.23]	.91
4. HGHE-A
Hi-G and hi-E AD groupc	16.1	1.60 [1.10, 2.34]*	.02
5. HGLE-A
Hi-G and low-E AD groupc	13.5	1.31 [0.77, 2.23]	.32
6. MGLE-A
Mod-G and low-E AD groupc	5.4	0.48 [0.22, 1.04]	.06
7. LGLE
Low-G and low-E group (ref.)	10.7	1.00 (ref. group)	(ref.)
Overall prevalence of CD	14.8
Individual contrast models
Contrast: HGHE-D vs. HGHE-A		1.42 [1.03, 1.95]*	.03
Contrast: HGLE-D vs. HGLE-A		1.10 [0.51, 2.39]	.81
Contrast: MGLE-D vs. MGLE-A		2.19 [0.81, 5.91]	.12

Notes: OR = odds ratio; CI = confidence interval; HG = high genetic; HE = high environmental; D = drug; G = genetic; E = environmental; LE = low environmental; MG = medium genetic; A = alcohol; LG = low genetic; ref. = reference.

^a P values for each group in the multifactorial model are compared with Group 7, the reference group;

^bDD: offspring risk due to twin or cotwin history of drug dependence with or without AD;

^cAD: offspring risk due to twin or cotwin history of alcohol dependence (without DD).