Stimulant dependência including amphetamines, methamphetamine or methcathinone is a transtorno of regulation of stimulant uso arising from repeated or continuous uso of stimulants. The characteristic feature is a strong internal drive to uso stimulants, which is manifested by impaired ability to control uso, increasing priority given to uso over other activities and persistence of uso despite harm or negative consequences. These experiences are often accompanied by a subjective sensation of urge or craving to uso stimulants. Physiological features of dependência may also be present, including tolerance to the effects of stimulants, abstinência symptoms following cessation or reduction in uso of stimulants, or repeated uso of stimulants or pharmacologically similar substances to prevent or alleviate abstinência symptoms. The features of dependência are usually evident over a period of at least 12 months but the diagnosis may be made if stimulant uso is continuous (daily or almost daily) for at least 3 months.