How do I know if someone is addicted to drugs?

If a person is compulsively seeking and using a drug(s) despite negative consequences, such as loss of job, debt, family problems, or physical problems brought on by drug abuse, then he or she probably is addicted. And while people who are addicted may believe they can stop any time, most often they cannot, and will need professional help—first to determine if they in fact are addicted, and then to obtain drug abuse treatment. Support from friends and family can be critical in getting people into treatment and helping them to maintain abstinence following treatment.