Just out of curiosity . . what do you guys do to lower and prevent your children's stress and anxiety levels? As in diet or whatever?
The reason I ask is that a lot of what you are describing are experimental coping mechanisms for stress.
Remember that kids feel stress and anxiety through diet issues and environmental pressures the same way adults do but have less sophisticated coping mechanism as well less control.
I am sure you can find adult parallels in "acting out" behaviors among your friends and acquaintances.
Something to think about for those of you that never payed attention in psych class