Table 1.

Demographic and clinical characteristics of adolescents with and without problematic Internet use

	Adolescents without PIU (N = 614)	Adolescents with PIU (N = 152)	p
Age	14.93 ± 1.28	15.60 ± 1.51	< 0.0001
Gender (female)	260 (42.34%)	23 (15.13%)	< 0.0001
Mean computer use time on weekdays (S.D.)	1.42 ± 1.56	2.56 ± 2.14	< 0.0001
Mean computer use time on weekends (S.D.)	2.59 ± 2.72	4.97 ± 3.79	< 0.0001
Mean smartphone using time during weekdays (hours per day) (S.D.)	3.51 ± 3.43	4.27 ± 3.42	0.015
Mean smartphone use time on weekends (S.D.)	4.58 ± 4.13	5.53 ± 4.47	0.014
Total sleep duration on weekdays	7:10 ± 1:39	6:48 ± 1:32	0.006
Total sleep duration on weekends	9:17 ± 2:08	9:11 ± 2:10	0.572
Mean bedtime on weekdays	23:49 ± 1:26	24:08 ± 1:05	0.004
Mean bedtime on weekends	24:16 ± 1:31	24:52 ± 1:35	< 0.0001
Mean wake up time on weekdays	6:59 ± 1:02	6:58 ± 0:56	0.757
Mean wake up time on weekends	9:42 ± 1:44	10:12 ± 1:58	0.001
Insomnia severity index total	8.96 ± 4.14	10.43 ± 4.31	< 0.0001
Epworth sleepiness scale total	6.30 ± 3.96	7.69 ± 4.52	< 0.0001
School sleep habit survey: Sleep-wake behavior scale total	11.92 ± 6.67	14.00 ± 8.26	.001
School sleep habit survey: morningness-eveningness (M-E scale) scale total	25.89 ± 3.68	25.11 ± 3.58	0.021
Ratio of evening type by M-E scale	152 (24.76%)	46 (32.26%)	0.179
Ratio of morning type by M-E scale	157 (25.57%)	23 (15.13%)	0.007
Children’s depression inventory total	14.70 ± 7.60	18.70 ± 8.64	0.001

PIU problematic Internet use, M-E morningness-eveningness