screaming issues/behavior

My son was is 4 yrs old,he use to scream and cry and be aggresive (aggressive) all day,his psychatrist started him on some depakote which helped alot,no more screaming when we are at home,but when we leave our house and go into a different enviorment like school or his therapy he really looses it,and gets back into the screaming stage,which his school and his therapy teachers can not deal with him,i dont think his school is going to last much longer,as he is a distraction to the other kids and just can not sit still,is there any other medication that can help this behavior so we can also have a life outside rather always be in the house.