Why does Joey get into trouble at school in the novel, Joey Pigza Swallowed the Key?

Joey Pigza is a young man with a hyperactivity disorder. He has had many problems in school, and as a result has been placed on medication for his disorder. However, the medication seems to work sporadically and as a result, Joey often finds himself wired and bouncing off the walls. He is unable to control his behavior when he gets into this state, which causes him to do things that get him into trouble such as talking back, fidgeting to the point of harming himself, and not paying attention, which results in harm to others.