. Author manuscript; available in PMC: 2014 Aug 1.

Published in final edited form as: Psychol Med. 2012 Nov 30;43(8):1713–1722. doi: 10.1017/S0033291712002735

Table 4.

Goodness-of-fit statistics for bivariate models of cannabis withdrawal and abuse/dependence.

	Model	Comparison model	Δχ²	Δdf	p-value
1	General ACE model; A, C, and E parameters equated between sexes
2	Drop the phenotypic correlation (drop all cross-paths)	1	696.23	3	<0.001
3	Drop genetic cross	1	11.64	1	<0.001
4	Drop shared environmental cross	1	0.36	1	0.55
5	Drop unique	1	57.04	1	<0.001

A= additive genetic influences, C = shared environmental influences, E = non-shared environmental influences