Which substance is NOT classified as a hallucinogen?

Cocaine is not classified as a hallucinogen; rather, it is classified as a stimulant. Stimulants primarily function by increasing the levels of certain neurotransmitters in the brain, which leads to heightened alertness, increased energy, and an elevated mood. Unlike hallucinogens, which alter a person's perception, mood, and cognitive processes, cocaine does not typically induce visual or auditory hallucinations or profound changes in perception.

On the other hand, LSD, PCP, and peyote are all substances that can induce hallucinogenic effects. LSD and peyote are classic hallucinogens that primarily affect serotonin receptors, leading to significant perceptual changes and hallucinations. PCP, although originally developed as an anesthetic, has hallucinogenic properties that can result in altered sensory perceptions and dissociative effects. Thus, recognizing these classifications helps to differentiate the pharmacological effects of these substances.