Table 3.

Model fit comparisons of selected models in model simplification for the 5-HTTLPR genotype

	Model fit indices				Model comparison test
	χ2	df	CFI	RMSEA		Δχ2	Δdf	p
Step 1.a
Unconstrained model	19.75	30	1.000	.000 (.000–.011)
Step 1.b
Constrained model	100.70	78	0.996	.022 (.004–.034)	1.b vs. 1.a	82.12	48	.002
Step 1.c
Freely estimated: BPADHD medication–family climate	74.44	75	1.000	.005 (.000–.023)	1.c vs. 1.a	54.68	45	.15
Step 2.1.a
Unconstrained model ADHD medication	74.44	75	1.000	.005 (.000–.023)
Step 2.1.b
Constrained model ADHD medication	No convergence				No convergence
Step 2.1.c
Freely estimated: WPStability path ADHD medication	78.20	84	1.000	.000 (.000–.019)	2.1.c vs. 2.1.a	5.58	9	.78
Step 2.2.1.a
Unconstrained model	78.20	84	1.000	.000 (.000–.019)
Step 2.2.1.b
Constrained model	131.20	93	0.994	.026 (.015–.036)	2.2.1.b vs. 2.2.1.a	62.78	9	< .001
Step 2.2.1.c
Freely estimated: WPStability path ADHD symptoms	91.57	91	1.000	.005 (.000–.023)	2.2.1.c vs. 2.2.1.a	15.41	6	.02
Step 2.2.1.d
Freely estimated: WPStability path school climate	81.97	87	1.000	.000 (.000–.020)	2.2.1.d vs. 2.2.1.a	3.90	3	.27
Step 2.2.2.a
Unconstrained model	81.97	87	1.000	.000 (.000–.020)
Step 2.2.2.b
Constrained model	101.95	96	0.999	.010 (.000–.025)	2.2.2.b vs. 2.2.2.a	22.33	9	.008
Step 2.2.2.c
Freely estimated: WPCorrelated change ADHD symptoms–family climate	86.93	93	1.000	.000 (.000–.019)	2.2.2.c vs. 2.2.2.a	4.87	6	.56
Step 2.2.3.a
Unconstrained model	86.93	93	1.000	.000 (.000–.019)
Step 2.2.3.b
Constrained model	120.02	105	0.997	.016 (.000–.027)	2.2.3.b vs. 2.2.3.a	35.77	12	< .001
Step 2.2.3.c
Freely estimated: WPCross-lagged path ADHD symptoms–family climate	96.13	102	1.000	.000 (.000–.019)	2.2.3.c vs. 2.2.3.a	9.23	9	.42

For abbreviations see Table 2