If it seems that your child is attracted to those with bad habits, reiterate why drug use is unacceptable. While you are teaching the facts about drugs, your child is getting lots of misinformation and mythology from peers. Marijuana smoke contains some of the same cancer-causing compounds as tobacco, sometimes in higher concentrations. Heroin is dangerous no matter how it's ingested. Once addicted to heroin, users may eventually switch to injecting the drug because it's cheaper.
Drug use is extremely unpredictable and affects people differently.
Anyone can become addicted to drugs. In any given school, most students aren't doing drugs. To protect consumers, medical protocol is set by health authorities and not determined by popular vote. The Food and Drug Administration withholds approval of a drug until studies strongly indicate that it is safe and effective for its intended use. Unless such studies determine that marijuana used medically fits that description, the American Medical Association recommends that the drug not be prescribed or used for medical purposes.