In 2008-2009, 8.4 percent of the U.S. population ages 12 or older had used an illicit drug in the past month; this rate was higher than that in 2007-2008 (8.0 percent). Data are presented for the use of specific illicit drugs. Nationally, 51.8 percent of Americans ages 12 or older reported using alcohol in the past month in 2008-2009. Alcohol-use rates increased in 11 States. Data are provided on binge drinking in the past month and by age groups. Nationally, 28 percent of the survey population for 2008-2009 used tobacco during the past month. Tobacco use decreased in seven States from the 2007-2008 surveys. The national rate in 2008-2009 for needing but not receiving treatment for an illicit drug problem was 2.5 percent. The percentage of persons needing but not receiving treatment for an alcohol problems was 7 percent in 2008-2009. Nationally, 4.6 percent of adults ages 18 or older had serious mental illness in the past year according to the 2008-2009 surveys. For adults ages 18 or older, 19.7 percent had "any" mental illness in 2008-2009; 3.7 percent of adults ages 18 or older had serious thoughts of suicide in the past year, and 6.5 percent in this age group had a major depressive episode in the past year. This rate was unchanged from 2007-2008. 43 references and appended State estimation methodology, tables of model-based estimates, comparison of the 2007-2008 and 2008-2009 model-based estimates, comparison of the 2002-2003 and 2008-2009 model-based estimates, and other sources of State-level data