According to the National Institute on Drug Abuse, one in ten people who try marijuana become addicted to the drug. It is not known, however, why some people become addicted to marijuana and others do not. Marijuana use is at its highest levels.
The daily use of marijuana by young people is at its highest levels since 1991. A national survey released in September indicated that 17 million Americans used marijuana last year. About 40 percent of those 17 million people used it for 20 or more days in the past month, up from 36.7 percent in 2009.
“It’s the biggest drug problem in the United States,” said Peter Delany of the Substance Abuse and Mental Health Services Administration.