What factor is most important in determining whether a substance is classified as a narcotic?

The classification of a substance as a narcotic primarily hinges on its potential for abuse and dependence. This is because narcotics are typically substances that induce pain relief (analgesia) but also have psychoactive effects that can lead to misuse. Due to the risks associated with their misuse, including addiction and overdose, regulatory bodies, including the Drug Enforcement Administration (DEA), assess the abuse potential in determining scheduling classifications.

While the chemical composition of a substance can play a role in understanding its effects and potential risks, it is the behavioral aspects—namely how likely it is to be misused or to lead to physical or psychological dependence—that are considered most critical in regulatory frameworks. The cost of a medication and its method of administration are secondary factors that do not significantly influence whether a substance is classified as a narcotic. Thus, the focus is rightly placed on the substance's potential for abuse and dependence when determining its classification.