From my experience with my son, I've learned:
Affect inappropriate to the situation is hypomania/mania.
The mood must be stabilized before even thinking about adding a stimulant (and some kids with mood disorders should not take stimulants at all).
Seroquel at 200 mg does not treat mania (it needs to be higher).
Seroquel XR does not always work as well as Seroquel (that's from my BiPolar (BP) online support group).
Some behaviors are just kids being kids and not related to mood disorders.
Hope you are able to sort everything out.
