evidence: MYTH: Marijuana isn’t addictive [...] Chronic marijuana use can lead to addiction. Research shows that approximately 9 percent, or about 1 in 11, of those who use marijuana will become addicted. This goes up to 17 percent in those who start using while young (in their teens) and increases to 25-50 percent of daily users.6 [...] FACTS: Like alcohol, marijuana and associated THC-containing products are intoxicants and can contribute to impaired judgment and increased susceptibility to mental health problems, including depression, insomnia and paranoid delusions.16