hallucinogen refers to any psychoactive substance , such as LSD or marijuana , that can produce delusions , hallucinations , paranoia , and altered sensory perception
Other /More definition:
Hallucinogen is defined as a substance that alters or distorts sensory impressions. It also refers to any psychoactive substance, like LSD or marijuana, that can produce delusions, hallucinations, paranoia, and altered sensory perception.
Moreover, Hallucinogens refer to psychoactive substances that cause abnormal perceptual experiences in the form of illusions or hallucinations, usually visual in nature. They are a diverse group of drugs that have powerful effects on mental and emotional functioning, marked most prominently by distortions in sensory and perceptual experience.
List of books: Hallucinogen