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

Table 3 Mean scores of Mood Inventory subcomponents according to quartiles of hours of mobile phone use in five weekdays

Mood Inventory subcomponents	Hours of mobile phone use in five weekdays				P for trend^a	P values^b (ANCOVA)	Bonferroni’s multiple comparison (P < 0.05)
Mood Inventory subcomponents	Quartile 1: <6 h/5 days	Quartile 2: 6–10 h/5 days	Quartile 3: 11–20 h/5 days	Quartile 4: ≥21 h/5 days	P for trend^a	P values^b (ANCOVA)	Bonferroni’s multiple comparison (P < 0.05)
Tension and excitement	13.8 (4.1)	14.0 (3.9)	14.0 (3.9)	14.7 (4.0)	<0.001	<0.002	Quartile 1 vs. quartile 4
Refreshing mood	13.9 (2.8)	13.9 (2.9)	13.9 (2.7)	14.0 (2.8)	0.616	0.947	–
Fatigue	15.4 (3.9)	16.0 (3.8)	16.0 (3.8)	16.5 (3.9)	<0.001	<0.001	Quartile 1 vs. quartile 2; quartile 1 vs. quartile 4
Depressed mood	15.3 (5.1)	15.7 (5.1)	15.5 (4.7)	16.4 (5.0)	<0.018	<0.007	Quartile 1 vs. quartile 4; quartile 3 vs. quartile 4
Anxious mood	17.4 (5.1)	17.7 (4.9)	17.6 (4.9)	18.0 (4.5)	0.212	0.454	–

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, adjusted for sex, school year, participation in sports club activities, mobile phone use experience, hours spent sleeping, and schools

ISSN: 1347-4715