NIDA - Nationwide trends in substance use (2015)
The Substance Abuse and Mental Health Services Administration (SAMHSA) conducts the annual National Survey on Drug Use and Health (NSDUH), a major source of information on substance use, abuse, and dependence among Americans 12 years and older. Survey respondents report whether they have used specific substances ever in their lives (lifetime), over the past year, and over the past month (also referred to as "current use"). Most analyses focus on past-month use.