. Author manuscript; available in PMC: 2012 Feb 1.

Published in final edited form as: Psychol Med. 2010 Apr 21;41(2):395–405. doi: 10.1017/S0033291710000589

Table 4.

Variance components from best-fit model

Variance component	MD	RU_C	ND_C	RU_S	ND_S
a²m	0.31 (0.22–0.40)	0.70 (0.64–0.74)	0.48 (0.41–0.54)	0.66 (0.61–0.68)	0.62 (0.56–0.66)
e²m	0.69 (0.66–0.74)	0.30 (0.30–0.36)	0.51 (0.45–0.58)	0.34 (0.31–0.34)	0.38 (0.37–0.39)
a²f	0.44 (0.39–0.49)	0.76 (0.76–0.76)	0.62 (0.62–0.63)	N.A.	N.A.
e²f	0.56 (0.50–0.59)	0.24 (0.20–0.26)	0.35 (0.31–0.39)	N.A.	N.A.

Values are heritability estimates and 95% confidence intervals.

MD, Major depression; RU_C, regular cigarette use; ND_C, nicotine dependence derived from cigarette use; RU_S, regular snus use; ND_S, nicotine dependence derived from snus use; a²m, heritability in males; e²m, environmental variance in males; a²f, heritability in females; N.A., not applicable; e²f, environmental variance in females.