Depression and suicidal behavior (Lissak, G. 2018).
Depression represents a growing public health concern and is a prevalent disease among adolescents. Findings have linked overall screen time to depression and suicidal behavior among adolescents (Wood & Scott, 2016; Maras et al., 2015). Liu, Wu, and Yao (2015) found a nonlinear dose-response relation between depressive symptoms and overall screen time among children in the age range of 5-18 who were using digital media for over two hours per day.
Symptoms of sleep disturbances are known to precede the development of depressive symptoms and suicidal behavior (Dombrovski et al., 2007). Therefore, inadequate sleep was suggested as a mediating factor linking nighttime screen use to depressive symptoms and suicidal feelings among junior high students (Oshima et al., 2012; Lemola, Perkinson-Gloor, Brand, Dewald-Kaufmann & Grob, 2015). Oshima et al. stressed the relationship between sleep disturbances and completed suicide. The authors also pointed out that negative mood, suicidal tendencies, and self-injury are likely to be related to mobile phones dependency, frequent message sending and prolonged worry about not receiving messages, especially before bedtime.