According to the U.S. Drug Enforcement Administration, drugs and other substances are separated into five categories, also known as schedules. Schedules are determined based on a few factors, such as the medical application of the substance and its abuse potential. 

Drug schedules range from I to V, with I being the most severe and V being the least. Because sentencing and penalties are often based on the schedule of the drug involved in a criminal charge, it is important to understand the differences between them. 

Schedule I

Schedule I drugs include heroin, LSD, marijuana, ecstasy, and others. These drugs are considered to have a high possibility of abuse and dependence. They are also not considered to have any medically accepted uses. 

Schedule II

While schedule II drugs are also considered to have a high possibility of abuse and dependence, these drugs are sometimes used medically. They include cocaine, methamphetamine, and prescription medications, such as Adderall, fentanyl, Vicodin, methadone, and Dilaudid, which is a powerful painkiller often used in hospital settings. 

Schedule III

Ketamine, codeine, and anabolic steroids are classed as schedule III drugs. Although these drugs do carry a risk of dependence, which can be both psychological and physical, their risk is considered low to moderate in comparison to schedule I and II drugs. 

Schedule VI

Many schedule VI drugs have applications as anti-anxiety or sleep medications. They include Ambien, Xanax, Valium, Ativan, and Tramadol. While used for medical purposes, using, carrying, or distributing these drugs without a prescription is illegal. 

Schedule V

Schedule V drugs have the lowest abuse and dependence potential. Over the counter cough medications, treatments for nerve pain, and gastrointestinal medications fall into this category.