Table 4.

Mediation of sleep quality/duration on association between screen activities and age 15 depressive symptom (N=2865).

Predictor	Model 1 Outcome: Age 15 Depressive Symptoms Direct Association	Model 2 Outcome: Age 15 Depressive SymptomsMediators Added	Model 3 Outcome: Age 15 Depressive SymptomsMediators and Age 9 Depression Added
Screen activities : Social messaging (hours)	.007^**	.003	.004
Problems falling asleep (0-7 day)		079^***	078^***
Problems staying asleep (0-7 day)		.034^***	.034^***
Sleep duration (hours)		−.025^**	−.026^***
Age 9 depressive symptoms (0-2)			.237^***
Adjusted R²	.036	.15	.16
Screen activities : Web-surfing (hours)	.018^***	.007	.007
Problems falling asleep (0-7 day)		079 ^***	078 ^***
Problems staying asleep (0-7 day)		.034^***	.034^***
Sleep duration (hours)		−.026^***	−.028^***
Age 9 depressive symptoms (0-2)			.24^***
Adjusted R²	.037	.154	.162
Screen activities : TV/movies (hours)	.017^**	.006	.005
Problems falling asleep (0-7 day)		079 ^***	078 ^***
Problems staying asleep (0-7 day)		.034^***	.033^***
Sleep duration (hours)		−.026^***	−.028^***
Age 9 depressive symptoms (0-2)			.232^***
Adjusted R²	.038	.155	.162
Screen activities : Gaming (hours)	.026^***	.017^***	.016^***
Problems falling asleep (0-7 day)		078^***	078^***
Problems staying asleep (0-7 day)		.033^***	.033^***
Sleep duration (hours)		−.025^***	−.027^***
Age 9 depressive symptoms (0-2)			.222^***
Adjusted R²	.044	.159	.166

Note. B=Unstandardized Coefficients (for ordinary least squares [OLS] regression).

p<.05

^**

p<.01

^***

p<.001.

Demographic covariates included in the analyses, but not shown in table for visual simplicity.