Which substances are classified as hallucinogens?

Hallucinogens are substances that alter a person's perception, mood, and various cognitive processes, often leading to experiences that seem real but are created by the mind. The classification of substances as hallucinogens includes those that predominantly cause hallucinations or significant alterations in sensory perception.

Marijuana, LSD, and PCP fall into this category due to their profound effects on thought processes, emotional state, and sensory perceptions. LSD, for example, is well-known for producing vivid visual and auditory hallucinations, while PCP can lead to substantial distortions in perception and behavior. Marijuana contains THC, which can alter perceptions and create a sense of euphoria or altered reality, especially at higher doses.

In contrast, the other options include substances that either do not alter perception in the same way or belong to entirely different categories. Alcohol and tranquilizers primarily act as depressants, reducing activity in the brain and leading to sedation rather than hallucinations. Caffeine and nicotine are stimulants that increase alertness and energy without altering sensory perception significantly. Heroin and morphine are classified as opioids, which primarily provide pain relief and sedation rather than hallucinations or altered reality. Thus, the correct grouping aligns with the unique characteristic of inducing hallucinatory experiences found in the substances listed