Table 2.

Model fit comparisons of selected models in model simplification for the DRD4 genotype

	Model fit indices				Model comparison test
	χ2	df	CFI	RMSEA		Δχ2	Δdf	p
Step 1.a
Unconstrained model	21.06	20	1.000	.008 (.000–.031)
Step 1.b
Constrained model	74.50	52	0.996	.022 (.009–.033)	1.b vs. 1.a	53.30	32	.01
Step 1.c
Freely estimated: BPADHD medication–family climate	53.41	50	0.999	.009 (.000–.024)	1.c vs. 1.a	32.34	30	.35
Step 2.1.a
Unconstrained model ADHD medication	53.41	50	0.999	.009 (.000–.024)
Step 2.1.b
Constrained model ADHD medication	241.64	58	0.968	.060 (.052–.068)	2.1.b vs. 2.1.a	204.71	8	< .001
Step 2.1.c
Freely estimated: WPStability path ADHD medication	63.91	56	0.999	.012 (.000–.025)	2.1.c vs. 2.1.a	8.98	6	.18
Step 2.2.1.a
Unconstrained model	63.61	56	0.999	.012 (.000–.025)
Step 2.2.1.b
Constrained model	97.31	62	0.994	.026 (.015–.035)	2.2.1.b vs. 2.2.1.a	33.70	6	< .001
Step 2.2.1.c
Freely estimated: WPStability path ADHD symptoms	64.89	60	0.999	.010 (.000–.023)	2.2.1.c vs. 2.2.1.a	1.24	4	.87
Step 2.2.2.a
Unconstrained model	64.89	60	0.999	.010 (.000–.023)
Step 2.2.2.b
Constrained model	79.77	66	0.998	.015 (.000–.026)	2.2.2.b vs. 2.2.2.a	16.54	6	.01
Step 2.2.2.c
Freely estimated: WPCorrelated change ADHD symptoms–family climate	67.34	76	0.999	.008 (.000–.022)	2.2.2.c vs. 2.2.2.a	2.33	4	.68
Step 2.2.3.a
Unconstrained model	67.34	76	0.999	.008 (.000–.022)
Step 2.2.3.b
Constrained model	98.10	72	0.996	.020 (.008–.030)	2.2.3.b vs. 2.2.3.a	35.50	8	< .001
Step 2.2.3.c
Freely estimated: WPCross-lagged path ADHD symptoms–family climate	72.12	70	1.000	.006 (.000–.021)	2.2.3.c vs. 2.2.3.a	4.73	6	.58

CFI Comparative Fit Index, RMSEA root mean squared error of approximation, ADHD attention-deficit/hyperactivity disorder, BP between-person level, WP within-person level