Association between mobile phone use and depressed mood in Japanese adolescents: a cross-sectional study

Table 2 Mean scores of the Mood Inventory subcomponents according to quartiles of hours of mobile phone use per week (weekdays and weekends)

Mood Inventory subcomponents	Hours of Mobile phone use per week				P for trend^a	P values^b (ANCOVA)	Bonferroni’s multiple comparison (P < 0.05)
Mood Inventory subcomponents	Quartile 1: <10 h/week	Quartile 2: 10–18 h/week	Quartile 3: 19–32 h/week	Quartile 4: ≥33 h/week	P for trend^a	P values^b (ANCOVA)	Bonferroni’s multiple comparison (P < 0.05)
Tension and excitement	13.8 (4.1)	13.8 (4.0)	14.0 (3.9)	14.6 (4.0)	<0.001	<0.001	Quartile 1 vs. quartile 4; quartile 2 vs. quartile 4
Refreshing mood	13.9 (2.8)	13.9 (2.9)	14.0 (2.8)	13.9 (2.7)	0.567	0.878	–
Fatigue	15.4 (4.0)	15.8 (3.8)	15.9 (3.7)	16.6 (4.0)	<0.001	<0.001	Quartile 1 vs. quartile 4
Depressed mood	15.4 (5.2)	15.5 (5.1)	15.3 (4.7)	16.5 (5.0)	<0.009	<0.002	Quartile 1 vs. quartile 4; quartile 2 vs. quartile 4; quartile 3 vs. quartile 4
Anxious mood	17.5 (5.2)	17.4 (4.8)	17.5 (4.8)	18.1 (4.6)	0.097	0.147	–

Data are presented as the mean with the SD in parenthesis
^aTested by multiple regression analysis, adjusted for sex, school year, participation in sports club activities, mobile phone use experience, hours spent sleeping, and schools
^bTested by analysis of covariance (ANCOVA), adjusted for sex, school year, participation in sports club activities, mobile phone use experience, number of hours spent sleeping, and school

ISSN: 1347-4715