Table 2 Factor effects on EEG intrahemispheric coherence.

	Without controlling psychological covariates			With controlling psychological covariates
	χ ²	p	Post hoc	χ ²	P	Post hoc
Delta
Group	6.033	0.049		1.568	0.456
Group × Region	2.795	0.986		3.363	0.972
Group × Hemisphere	6.771	0.034		6.714	0.035
Group × Region × Hemisphere	0.964	1.000		1.192	1.000
Theta
Group	9.117	0.010		1.414	0.493
Group × Region	2.628	0.989		3.006	0.981
Group × Hemisphere	5.746	0.057		4.090	0.129
Group × Region × Hemisphere	2.544	0.990		2.651	0.988
Alpha
Group	3.047	0.218		6.935	0.031
Group × Region	4.831	0.902		5.458	0.859
Group × Hemisphere	1.329	0.515		0.909	0.635
Group × Region × Hemisphere	5.007	0.891		4.566	0.918
Beta
Group	8.414	0.015	I > H	10.165	0.006
Group × Region	4.963	0.894		5.626	0.846
Group × Hemisphere	0.874	0.646		0.893	0.640
Group × Region × Hemisphere	5.001	0.891		4.676	0.912
Gamma
Group	10.826	0.004	I > H	25.737	< 0.001	I > A, I > H
Group × Region	2.211	0.994		2.477	0.991
Group × Hemisphere	0.467	0.792		0.571	0.752
Group × Region × Hemisphere	0.032	1.000		1.279	0.999

Effects on EEG intrahemispheric coherence with or without controlling effects of psychological variables (scores on the BDI-II, BAI, and BIS-11) were analyzed separately for each frequency band. Effects of demographic data (age, education, and IQ) variables were controlled in all conditions. Bonferroni correction was applied to the post hoc analysis, and the significance level was set at 0.0167. Fisher’s Z-transformed scores were used for the EEG data. The group factor consists of IGD (n = 30), AUD (n = 30), and HC (n = 32). The region factor consists of following pairs: fronto-central, fronto-temporal, fronto-parietal, centro-temporal, centro-parietal, temporoparietal. The hemisphere factor consists of left and right side. EEG = electroencephalography; IGD (I) = Internet gaming disorder; AUD (A) = alcohol use disorder; HC (H) = healthy control; IQ = intelligence quotient; BDI-II = Beck Depression Inventory-II; BAI = Beck Anxiety Inventory; and BIS-11 = Barratt Impulsivity Scale-11.

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