How can I tell if someone has a drug problem?

If a person continues to seek and use a drug despite negative effects on their life then they are probably addicted or have some form of a drug use disorder. And while many people who are addicted believe they can stop any time, usually they can’t. Hiding addiction gets harder, especially when it leads to things like bad grades, fighting with friends and family, legal issues, or getting kicked off a sports team. To learn why drugs are so hard to quit, see this video: