Schedule IV is the category of drugs, such as heroin, that are considered to have "particularly dangerous properties" in comparison to other drugs (ethanol is left unregulated). According to , "The drugs in Schedule IV shall also be included in Schedule I and subject to all measures of control applicable to drugs in the latter Schedule" as well as whatever "special measures of control"; each Party deems necessary. This is in contrast to the U.S. Controlled Substances Act, which has five Schedules ranging from Schedule I (most restrictive) to Schedule V (least restrictive), and the Convention on Psychotropic Substances, which has four Schedules ranging for Schedule I (most restrictive) to Schedule IV (least restrictive).