Sweet personality symptoms and conditions

My 4year old grandson has been on 20mg adderall Xr for aprox 2 months .. It has helped with his hyperness but soon after taking the drug he becomes emotionl and completely beligerant. He acts out and screams at you. This goes on for hours. Ive discussed this with doctor and he wants to up the dose.. Almost afraid to. Dont want to think that grandson could get anymore beligerant. He was hyper before the meds not beligerant. Where can I go to find more on this.?