Why does Seroquel cause weight gain?!

Why does Seroquel cause weight gain?

Does it lower metabolism? Increase appetite? Something else?

4 weeks ago
It's being prescribed off-label for Post Traumatic Stress Disorder and anxiety disorder.

I am sure there is a more chemical bioavailability answer that is more specific, but from experience I can answer that the drug makes you so tired and lathargic that you become more sediatary and that causes some weight gain....

I doubt that is it, but it makes some sense from what I have experiecned with the drug........