I read this interesting article yesterday. It shows that teens with late bedtimes (who don't get enough sleep) are much more likely to get depressed and even have suicidal thoughts. The article points out that the growing reach of technology (Facebook, texting, etc.) may lead to teens staying up too late.
This is just another example of what happens when people try to go against natural patterns. Daytime is for activity, nighttime is for sleep. This has been the way for millions of years. If you try to go against these natural circadian rhythms, you pay the price in one way or another.
