Which of the following is an example of a hallucinogen?

LSD, or lysergic acid diethylamide, is classified as a hallucinogen due to its powerful effects on perception, mood, and cognitive processes. When consumed, LSD interacts with serotonin receptors in the brain, leading to altered visual and auditory perceptions, which may include visual hallucinations, synesthesia, and profound changes in thought patterns and emotional experiences. Users often report experiencing vivid imagery and a distorted sense of time and self.

In contrast, cocaine and methamphetamine are classified as stimulants. They primarily increase energy and alertness and can lead to feelings of euphoria but do not produce the hallucinatory effects characteristic of hallucinogens. Alcohol is classified as a depressant, affecting the central nervous system by slowing down brain activity and impairing cognitive functions, rather than inducing hallucinations.