Drugs, substances, and certain chemicals used to make drugs are classified into five (5) distinct categories or schedules depending upon the drug's acceptable medical use and the drug's abuse or dependency potential.

The abuse rate is a determinate factor in the scheduling of the drug; for example, Schedule I drugs have a high potential for abuse and the potential to create severe psychological and/or physical dependence. As the drug schedule changes - Schedule II, Schedule III, etc., so does the abuse potential - Schedule V drugs represents the least potential for abuse.

Schedule I
	Schedule I drugs, substances, or chemicals are defined as drugs with no currently accepted medical use and a high potential for abuse. Some examples of Schedule I drugs are: Heroin, LSD, Marijuana (Cannabis), Ecstasy, Methaqualone, and Peyote.
Schedule II
	Schedule II drugs, substances, or chemicals are defined as drugs with a high potential for abuse, with use potentially leading to severe psychological or physical dependence. These drugs are also considered dangerous. Some examples of Schedule II drugs are: Vicodin, Cocaine, Methamphetamine, Methadone, Dilaudid, Demerol, OxyContin, Fentanyl, Dexedrine, Adderall, and Ritalin.
Schedule III
	Schedule III drugs, substances, or chemicals are defined as drugs with a moderate to low potential for physical and psychological dependence. Schedule III drugs abuse potential is less than Schedule I and Schedule II drugs but more than Schedule IV. Some examples of Schedule III drugs are: Tylenol with Codeine, Ketamine, Anabolic Steroids, Testosterone.
Schedule IV
	Schedule IV drugs, substances, or chemicals are defined as drugs with a low potential for abuse and low risk of dependence. Some examples of Schedule IV drugs are: Xanax, Soma, Darvon, Darvocet, Valium, Ativan, Talwin, Ambien, Tramadol.
Schedule V
	Schedule V drugs, substances, or chemicals are defined as drugs with lower potential for abuse than Schedule IV and consist of preparations containing limited quantities of certain narcotics. Schedule V drugs are generally used for antidiarrheal, antitussive, and analgesic purposes. Some examples of Schedule V drugs are: Robitussin AC, Lomotil, Motofen, Lyrica, Parepectolin.

As of 2019 CBD with less than .3% THC is considered to be schedule 5

Excerpts from https://www.dea.gov/drug-scheduling