The category of stimulants includes cocaine, amphetamine, and amphetamine-like substances. According to the National Survey on Drug Use and Health there were an estimated 1 million new cocaine users in 2004, and about 1% of the U.S. population ages 12 years or older had used cocaine within the past 30 days (Substance Abuse and Mental Health Services Administration 2005). Amphetamine-type substances come in several different forms. Powdered methamphetamine hydrochloride ("speed," "meth," or "crank") can be snorted, injected, or dissolved in beverages. Pills can be prescription medications such as dexamphetamine or clandestinely manufactured tablets of powdered methamphetamine. Freebase methamphetamine (sometimes called "ice") can be vaporized in a pipe or on aluminum foil and insufflated (smoked), producing as rapid a high as with injection but without having to use needles (Maxwell 2005). The United Nations Office on Drugs and Crime estimated that 30 million people worldwide are using amphetamine-type stimulants, primarily methamphetamine, compared with an estimated 15 million people who use opioids and 13 million who use cocaine (United Nations Office on Drugs and Crime 2004). The geographical spread of methamphetamine use is being seen in both rural and urban settings. Alarmingly, although the total number of past-year and past-month methamphetamine users did not change significantly between 2002 and 2004, the number of past-month methamphetamine users who met criteria for abuse or dependence increased from 27.5% in 2002 to 59.3% in 2004 (Substance Abuse and Mental Health Services Administration 2005).