My son started Vyvanse yesterday - took 1/2 of a 20 mg capsule (dissolved in H20) with toast. He noticed the ability to concentrate and focus. He even read 3 chapters of a book - willingly! However, today I gave him the other 1/2 dose - woke him early so it would "kick in" by school. He threw up (mostly dry heave) about 30 minutes later. We will try tomorrow with food. Very anxious about potential side affects. Don't want to have to keep uping the dose down the road to maintain effectiveness - don't want risk of addiction and/or withdrawal issues that are so severe he can't go off. CAN you go off of this for good at some point?