Which of the following is classified as a hallucinogen?

LSD, or lysergic acid diethylamide, is classified as a hallucinogen due to its potent ability to alter an individual’s perception, mood, and cognitive processes. Hallucinogens, such as LSD, primarily affect serotonin receptors in the brain, leading to significant changes in sensory perception, including visual and auditory hallucinations. Users may experience distortions of reality, enhanced emotional responses, and an altered sense of time and space.

In contrast, substances like oxycodone and heroin are classified as opioids and are primarily used for pain relief, with effects that mainly suppress the central nervous system rather than create hallucinatory states. Meperidine is also an opioid analgesic, used for pain management, and does not produce the hallucinogenic effects characteristic of LSD. Thus, when identifying hallucinogens, LSD stands out distinctly as it is specifically recognized for its unique effects on perception and consciousness.