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4. Office of Applied Studies, Substance Abuse and Mental Health Services Administration (SAMHSA) The NSDUH report: Nonmedical users of pain relievers: Characteristics of recent initiates 2006 http://www.samhsa.gov/data/2k6/pain/pain.pdf
5. Substance Abuse and Mental Health Services Administration Center for Behavioral Health Statistics and Quality The DAWN report: Highlights of the 2011 Drug Abuse Warning Network (DAWN) findings on drug-related emergency department visits 2011 http://www.samhsa.gov/