Abuse liability is the potential that a drug has for addiction. The term is used interchangeably with “potential for addiction” and “addiction-sustaining properties”. In the United States, scientists employed by drug companies must determine the abuse liability of any new drug that the company wants to manufacture and sell. Drug company officials fill out either a New Drug Application or a Biologics License Application (if the medicine is biologic) and then submit it to the U.S. Food and Drug Administration (FDA). Next the company must conduct extensive tests on laboratory animals and humans to determine if the drug is addictive or harmful, how quickly it is absorbed into the body and how effective it is at treating a condition or illness.
Abuse liability tests also determine if certain ways of administering the drug make it more addictive. For example, does taking it by injection produce a “rush” of pleasure that is different from taking it in a time-released form? Testing should also determine whether a patient can build up a tolerance to the drug — that is, if he needs more to produce the same effects, and if the drug produces withdrawal symptoms when he stops using it.
The final step is for statisticians at the FDA Center for Drug Evaluation and Research to go over the drug company’s test process and determine if the tests did indeed follow rigorous protocol. If this is so, they will approve the drug for sale. If a drug has a great deal of abuse liability and only a small medical benefit, the FDA may not allow it to be sold because of the potential danger to public health.
If the new drug has a potential for abuse, the FDA may approve it as a governmentally controlled substance. Controlled substances are drugs that may or may not have medical uses, but are regulated by the government because they are addictive. The government currently has five levels of abuse potential, with Schedule I drugs being the most highly regulated and Schedule 5 drugs having less potential for abuse and therefore needing fewer restrictions.