Sedative, hypnotic or anxiolytic dependência is a transtorno of regulation of sedative uso arising from repeated or continuous uso of these substances. The characteristic feature is a strong internal drive to uso sedatives, hypnotics, or anxiolytics, 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 these substances. Physiological features of dependência may also be present, including tolerance to the effects of sedatives, hypnotics or anxiolytics, abstinência symptoms following cessation or reduction in uso, or repeated uso of sedatives 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 sedative uso is continuous (daily or almost daily) for at least 3 months.