Dr. Sanjay Gupta, the Chief Medical Correspondent at CNN, reported on the rate of addiction of people who use illicit drugs.
According to his article, various studies have found that up to 10 percent of marijuana users become addicted and dependent on the drug. 20 percent of cocaine users become dependent after using, and up to 25 percent of heroin users become addicted.
Nearly 30 percent of cigarette smokers become addicted to cigarettes.
Source: Sanjay Gupta, “Why I changed my mind on weed,” CNN, August 9, 2013.