Teens who use drugs do so to "reduce anxiety and stress," CDC report says. Almost half of the young people interviewed said they used narcotics to "not worry about a problem or erase bad memories" An expert warns that if a teenager says that "it's a big warning sign" that she needs help.

The majority, 84%, used some type of marijuana. This comes amid growing evidence linking cannabis use to psychotic disorders. Less than half (49%) reported having drunk alcohol and 19% of teens surveyed reported abusing prescription medications.