You shouldn't abuse medication.
Xavier gets his wisdom teeth removed and is prescribed a sedative to help him with the pain.
Xavier wants to block out the pain.
Xavier takes the sedatives to dull the pain and deals with the pain when it's not so bad.
Xavier takes more than the recommended dose of sedatives, so he feels less pain.
Xavier learns to deal with the pain and continues to function as normal.
Xavier becomes dependent on the sedatives and finds ways to get more, becoming an addict.