What category of drugs includes substances that cause hallucinations and alter reality?

Hallucinogens are a specific category of drugs known for their profound effects on perception, mood, and various cognitive processes. These substances can induce hallucinations—sensory experiences that appear real but are created by the mind. They alter an individual's sense of reality and may affect visual, auditory, and tactile perceptions, leading to experiences that can be both vivid and sometimes disorienting.

This classification includes notable examples such as LSD (lysergic acid diethylamide), psilocybin (found in magic mushrooms), and mescaline. By causing significant alterations in thought processes and sensory perception, hallucinogens can lead users to perceive things that do not exist in the external world, fundamentally distinguishing them from other drug categories.

In contrast, stimulants are substances that increase activity in the central nervous system, depressants slow down brain function and processing, and analgesics are primarily used to relieve pain. Each of these other categories serves different purposes and has distinct physiological effects on the body, thus not fitting the definition of substances that cause hallucinations and alter reality.