The Controlled Substances Act has been expressly formulated for maintaining regulatory oversight over the prescribing, administering and dispensing of Scheduled Drugs I to V that have the potential for misuse, abuse and addiction. The District Enforcement Administration (DEA) has been entrusted with the mammoth task of enforcing the controlled substance regulations across the USA.
Source: http://titangroupdea.jigsy.com/entries/general/understanding-the-dea-forms-for-controlled-substances