The Controlled Substances Act (CSA) places all substances which were in some manner regulated under existing federal law into one of five schedules.
This placement is based upon the substance’s accepted medical use, potential for abuse, and safety or dependence liability.
The Act also provides a mechanism for substances to be controlled (added to or transferred between schedules) or decontrolled (removed from control). The procedure for these actions is found in Section 201 of the Act (21U.S.C. §811).