Which substance is categorized as a Schedule 4 drug?

Alprazolam, commonly known by its brand name Xanax, is classified as a Schedule IV controlled substance. This classification is primarily due to its potential for abuse and dependency, although it is deemed to have a lower risk compared to substances classified in higher schedules.

The scheduling of drugs is determined by their medical use, safety, and the likelihood of dependence or abuse. Schedule IV substances are accepted for medical use and have a low potential for abuse relative to substances in Schedules I through III. Alprazolam is used primarily for the treatment of anxiety disorders and panic disorders due to its anxiolytic properties.

In this context, other substances listed have different classifications: Depo-Testosterone is classified as a Schedule III drug due to its anabolic steroid properties, Fluoxetine is not a controlled substance as it is an antidepressant with a lower risk of abuse, and Nabilone is classified as a Schedule II substance, typically due to its potential for abuse as a cannabinoid. Hence, the choice of Alprazolam as a Schedule IV drug is correct.