In fact, researchers conducting a recent longitudinal study of adolescents found that greater use of mobile phones at baseline was associated with higher levels of depression 1 year later.19
I thought this was interesting as I too feel like too much gaming or activity on mobile devices inside could lead to depression. I think this because you may not be doing enough social and physical activity and spending all your time staring at a mobile device or tv screen can sometimes lead to feeling alone and getting out of physical shape and becoming depressed.