. Author manuscript; available in PMC: 2015 May 14.

Published in final edited form as: Psychol Med. 2011 Aug 11;42(3):497–508. doi: 10.1017/S0033291711001401

Table 2.

Results of model fitting for symptoms of disordered gambling (DG) using twin and sibling pairs

		Sex effects
Model	Description	Qualitative	Quantitative	Δ χ ²	Δdf	ΔAIC
I^a	ACET	+	+	–	–	–
II	ACET	+	–	+ 0.702	+3	–5.298
III	ACET	–	–	+ 0.702	+ 5	–9.298
IV	ACE	–	–	+ 0.709	+6	–11.291
V	CE	–	–	+ 22.929	+7	+ 8.929
VI^b	AE	–	–	+ 0.731	+7	–13.269

A, Additive genetic effects; C, shared environment; E, individual-specific environment; T, special twin environment; df, degrees of freedom; AIC, Akaike's Information Criterion.

–2 log likelihood = 1601.027, df = 1738, AIC =–1874.973.

Best-fit model.