Hallucinogens are a general group of pharmacological agents that can be divided into three broad categories:
The universal effects that these classes of psychoactive drugs have in common is that they can cause subjective changes in perception, thought, emotion and consciousness. Unlike other psychoactive substances (such as alcohol, stimulants and opioids) these substances do not merely amplify or dull ordinary states of consciousness, but rather induce experiences that are qualitatively different from them. These experiences are often compared to non-ordinary forms of consciousness such as lucid dreaming, meditation, religious, mystical or transpersonal experiences, hallucinations, dreams and acute or persisting states of psychosis.
List of hallucinogens