Rebound — the change in mood and behavior when stimulant medication wears off — is very common for kids with ADHD. Some physicians add a short-acting medication in the afternoons to ease this transition. Sometimes, a change in medication is best. Ultimately, you need to work with the prescribing doctor on this.
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism