Table 4. Model fit.

Model	χ2 / df (p)	CFI	RMSEA	AIC	χ2diff / dfdiff (pdiff)
Internalizing
M1.1 (baseline) cs = 0	68,25 / 69 (.503)	>.999	<.001	170,254
M1.2 i = 0	68,68 / 69 (.488)	>.999	<.001	170,682
M2 cs = 0, o. eq.	83,14 / 83 (.510)	>.999	.001	157,144	14,89 / 14 (.386)
M3 (final model) cs = i = m = f = 0; o. eq	85,00 / 86 (.468)	>.999	<.001	153,002	16,75 / 17 (.472)
Externalizing
M1.1 (baseline) cs = 0	66,54 / 69 (.562)	>.999	<.001	168,536
M1.2 i = 0	74,92 / 69 (.292)	.976	.005	176,92
M2 cs = 0, o. eq.	95,88 / 88 (.158)	.960	.007	169,883	29,35 / 14 (.009)
M3 (final model) cs = m = f = ct = 0	69,00 / 78 (.757)	>.999	<.001	152,996	2,46 / 9 (.982)

M, Model; C, birth cohort; cs, environmental effects shared by siblings; i, non-additive genetic effects; m, environmental transmission from mother to offspring; f, environmental transmission from father to offspring; ct, environmental influences shared by twins; o. eq., all other Parameters were set equal across cohorts