Table 2.

Sample Sizes by Risk Group: Combined MATCH and PACER Samples

Risk Group	ADa		CannDb		AD or CannD
	ntwins	noffspring	ntwins	noffspring	ntwins	noffspring
1. Parent affected	189	312	79	129	222	362
2. Parent UN, MZ cotwin affected	37	62	33	53	50	83
3. Parent UN, DZ cotwin affected	74	122	47	79	76	131
4. Parent and cotwin UN	484	822	610	1031	436	742

Note. AD = alcohol dependence; CannD = cannabis dependence; UN = unaffected (neither alcohol nor cannabis dependent).

^acoded without regard to cannabis dependence.

^bcoded without regard to alcohol dependence.