Which of the following substances is classified as a CNS depressant?

Xanax, classified as a benzodiazepine, is a central nervous system (CNS) depressant. Benzodiazepines enhance the effect of a neurotransmitter called gamma-aminobutyric acid (GABA), which slows down brain activity. This action can lead to effects such as sedation, relaxation, and reduced anxiety, making Xanax a commonly prescribed medication for anxiety disorders and panic disorders.

In contrast, substances like nicotine and Adderall are CNS stimulants. Nicotine increases alertness and energy, while Adderall, which contains amphetamine, enhances focus and attention by increasing the levels of certain neurotransmitters. Benzedrine, an early form of amphetamine, also acts as a stimulant.

Understanding the classifications of these substances is important in addiction treatment and management, as it informs how they affect the brain and the potential for misuse or dependency. Therefore, Xanax is the substance that fits the classification of a CNS depressant among the provided options.