One of the fastest growing illicit drug problems in the world between 1995 and 2005 has been the use and abuse of methamphetamine (MA). According to estimates by the United Nations Office on Drugs and Crime (2005), approximately 26 million people around the world used amphetamines in a 12-month period during 2003–2004. In contrast, approximately 11 million people used heroin and 14 million used cocaine. Statistics on the extent of the MA problem within the United States create a somewhat mixed picture. According to the National Survey of Drug Use and Health, in 2004 an estimated 12 million people had used MA at least once in their lifetime, 1.4 million had used it in the previous year, and 600,000 had used it in the previous 30 days (SAMHSA Office of Applied Studies 2005). Although these estimates have been stable since 2002, the number of previous-month users who met criteria for stimulant abuse or dependence increased from 63,000 in 2002 to 130,000 in 2004. Therefore, according to National Survey of Drug Use and Health data, although the number of new users remains relatively stable, a higher percentage of people who use MA are developing significant clinical disorders as a result of their use.