Scientists at the U.S. Department of Health and Human Services have completed the first comprehensive analysis of the prevalence of prescription stimulant use, misuse, use disorders, and motivations for misuse in the U.S. adult population. Looking at annual averages, approximately 6.6% (or 16 million) of U.S. adults used prescription stimulants in the preceding year; 4.5% (or 11 million) used prescription stimulants appropriately (without misuse); 2.1% (or 5 million) misused prescription stimulants at least once; and 0.2% (or 0.4 million) had prescription stimulant use disorders. The article analyzed data from the 2015 and 2016 National Surveys on Drug Use and Health conducted by the Substance Abuse and Mental Health Administration (SAMHSA).