Yes this makes sense for lack of sleep to be the cause of mental health issues rising for teens. Many teens stay up much later than they have to because of distractions, like phones, or other issues. But a main issue are the phones, this is causing teens to stay up and lose the crucial sleeping hours they need to be able to function properly and efficiently. I have noticed at times where i have not gotten enough sleep over a period of time, I am a lot more grumpier, lazy, unmotivated, look and feel worse, and just dont feel good in general. Once you realize how much rest actually effects your life, its much easier to put down those distractions so that you can benefit more. Especially as teens, its hard to accept that and be aware of it to make that difference, but it would definitely help with the rise of mental health.