Cannabis is the most commonly used illicit substance in the US
About 7% of Americans are current marijuana users compared to less than 1% for cocaine, heroin, and methamphetamine (“Results from the 2010 National Survey on Drug Use and Health: Summary of National Findings” report from the Substance Abuse and Mental Health Services Administration http://1.usa.gov/154HYiq)
Among first-time cannabis users, 2% will develop addiction within a year, increasing to 6% after a decade (Lopez-Quintero C et al, Drug Alcohol Depend 2011;115(1–2):120–130)
Each year, 1.5% of Americans struggle with active addiction to cannabis (Stinson FS et al, Psychol Med 2006;36(10):1447–1460)
Patients with CUD comprise 17% of admissions for substance abuse treatment (The Substance Abuse Mental Health Services Administration (SAMHSA) (2012) Treatment Episode Data Set, www.samhsa.gov/data/DASIS.aspx)
Approximately 50% of the cannabis admissions are for those 25 years of age or younger
More than 75% of patients resume marijuana use within a year of program discharge (Sinha R, Curr Psychiatry Rep 2011;13(5):398–405), although most do not relapse back to full-blown addiction
23% of patients with psychosis are current cannabis users (Green B et al, Br J Psychiatry 2005;187(4):306–313)
36% of teens seeking treatment for cannabis use disorder (CUD) had internalizing disorders (depression and anxiety) and 59% had externalizing problems (conduct disorder and attention-deficit/hyperactivity disorder) (Dennis M et al, J Subst Abuse Treat 2004;27(3):197–213)