Unknown or não especificado psychoactive substance dependência is a transtorno of regulation of uso of an unknown or não especificado substance arising from repeated or continuous uso of the substance. The characteristic feature is a strong internal drive to uso the unknown or não especificado substance, 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 the unknown or não especificado substance. The features of dependência are usually evident over a period of at least 12 months but the diagnosis may be made if uso of the unknown or não especificado substance is continuous (daily or almost daily) for at least 3 months.