Which of the following is an example of a depressant?

A depressant is a substance that reduces the functional activity of the central nervous system, leading to a calming effect, decreased anxiety, and sedation. Xanax, which is a brand name for the medication alprazolam, falls into the category of benzodiazepines. Benzodiazepines are commonly prescribed to treat anxiety and panic disorders and have a sedative effect on the brain.

When taken, Xanax enhances the effect of a neurotransmitter called gamma-aminobutyric acid (GABA), which results in a decrease in neural activity. This suppression of the central nervous system makes Xanax effective in promoting relaxation and improving sleep, thereby clearly fitting the definition of a depressant.

In contrast, substances like cocaine and LSD are stimulants and hallucinogens, respectively, which increase nervous system activity and produce heightened states of alertness or altered perceptions, rather than calming effects. Aerosols, depending on their composition, can also have stimulant or hallucinogenic properties rather than being classified strictly as depressants.