Table 3.

Stratified logistic regression analyses of PSU and mental health symptoms across education modes.

Dependent variable	Subgroup	No. of participants	No. of symptoms	Prevalence	Crude ORsa	Adjusted ORsb	P for
				(%)	(95% CI)	(95% CI)	interaction
Depressive symptoms	Total sample	1629	423	25.97
	PSU	953	334	35.05	3.37(2.45-4.64)	3.14(2.26–4.37)	0.015
	Non-PSU	676	89	13.17	1	1
	Online group	788	236	29.95
	PSU	495	205	41.41	4.31(2.64-5.67)	4.66(2.83–6.75)
	Non-PSU	293	31	10.58	1	1
	Face-to-face group	841	187	22.24
	PSU	458	129	28.17	2.39(2.38-4.85)	2.33(2.31–4.82)
	Non-PSU	383	58	15.14	1	1
Anxiety symptoms	Total sample	1629	357	21.92
	PSU	953	264	27.70	3.51(2.42-5.07)	3.73(2.13–4.59)	0.021
	Non-PSU	676	93	13.76	1
	Online group	788	198	25.13
	PSU	495	163	32.93	5.67(3.46-9.09)	6.05(3.49–9.67)
	Non-PSU	293	35	11.95	1	1
	Face-to-face group	841	159	18.91
	PSU	458	101	22.05	3.09(2.04-4.67)	2.94(1.93–4.49)
	Non-PSU	383	58	15.14	1	1
Insomnia symptoms	Total sample	1629	1189	72.99
	PSU	953	761	79.85	2.97(2.27-3.88)	2.96(2.23–3.92)	0.589
	Non-PSU	676	428	63.31	1	1
	Online group	788	598	75.89
	PSU	495	415	83.84	3.24(2.87-5.35)	3.29(2.87–5.72)
	Non-PSU	293	183	62.46	1	1
	Face-to-face group	841	591	70.27
	PSU	458	346	75.55	2.87(2.13-3.87)	2.86(2.11–3.89)
	Non-PSU	383	245	63.97	1	1

PSU, problematic smartphone use; OR, odds ratio.

^aNon-adjusted model.

^bAdjusted for age, sex, grade, educational level, residence, satisfaction, and exercise habits.

Participants with no PSU comprised the reference groups.