Final answer:
DEA Classification is the rating that relates to a substance's medical usability and potential for abuse, with Schedule I drugs being the most restricted due to high abuse potential and no accepted medical use.
Step-by-step explanation:
The DEA Classification is a rating attributed to the medical use of a substance and its potential for abuse. The Drug Enforcement Administration (DEA) schedules substances based on their accepted medical use, the potential for abuse, and the potential for dependence. Drugs classified under DEA Schedules I through V decrease in potential for abuse and dependency from I to V, with Schedule I drugs having the highest potential for abuse with no accepted medical use, and Schedule V drugs having the lowest potential for abuse and accepted medical use.