Table IV.

Standardized Estimates (and 95% CIs) for A, C, and E Influences on Drinking Initiation and Frequency of Alcohol Use at Age 17 for the Full Models Constrained Across Gender in the Combined Model and for FinnTwin16 and FinnTwin12 Separately

Variable	A	C	E
	Combined
Alcohol initiation	0.29 (0.22–0.37)	0.59 (0.51–0.66)	0.12 (0.10–0.14)
Frequency of use	0.39 (0.30–0.49)	0.34 (0.25–0.42)	0.27 (0.24–0.30)
	FinnTwin16
Alcohol initiation	0.34 (0.24–0.45)	0.55 (0.45–0.64)	0.11 (0.09–0.13)
Frequency of use	0.44 (0.32–0.57)	0.31 (0.19–0.42)	0.25 (0.22–0.29)
	FinnTwin12
Alcohol initiation	0.23 (0.12–0.35)	0.64 (0.52–0.74)	0.13 (0.11–0.17)
Frequency of use	0.32 (0.17–0.47)	0.38 (0.24–0.51)	0.30 (0.26–0.36)

A = additive genetic influences; C = common environmental influences; E = unique environmental influences.