Which of the following is an example of a hallucinogen?

• A. Alcohol
• B. LSD
• C. Caffeine
• D. Cocaine

Answer: (B)

Hallucinogens cause noticeable changes in perception, mood, and thought, often with vivid visual or auditory distortions and altered sense of time. LSD is a classic example of a psychedelic hallucinogen; it primarily affects serotonin signaling in the brain, especially 5-HT2A receptors, which reshapes how sensory input is processed and can lead to vivid perceptual distortions and unusual experiences. Among the options, this is the one that fits the hallucinogen category.

Alcohol is a depressant that slows brain activity and impairs judgment and coordination, not defined by producing true perceptual hallucinations. Caffeine is a stimulant that increases wakefulness and energy, with no hallmark perceptual hallucinations. Cocaine is also a stimulant, elevating mood and alertness by boosting dopamine, but it does not produce the characteristic sensory distortions of a hallucinogen.