• Any naturally-derived or synthetic substance that can induce hallucinations.
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• Class of drugs capable of inducing illusions, hallucinations, delusions, paranoid ideations, and other alterations of mood and thinking; the feature that distinguishes these agents from other classes of drugs is their capacity to induce states of altered perception, thought, and feeling that are not experienced otherwise.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Drugs capable of inducing illusions, hallucinations, delusions, paranoid ideations, and other alterations of mood and thinking. Despite the name, the feature that distinguishes these agents from other classes of drugs is their capacity to induce states of altered perception, thought, and feeling that are not experienced otherwise.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• (psychotomimetic drug) Drugs which produce a state similar to that of psychosis.
  CRISP Thesaurus
  National Institutes of Health, 2006
• Hallucinogens are a diverse group of drugs that can cause highly unpredictable, idiosyncratic reactions. Intoxication typically causes hallucinations, with altered perception, impaired judgment, ideas of reference, and depersonalization. There is no stereotypical withdrawal syndrome. Diagnosis is clinical. Treatment is supportive.
  Merck Manuals
  Merck & Co., Inc., 2020
• Hallucinogen, substance that produces psychological effects that tend to be associated with phenomena such as dreams or religious exaltation or with mental disorders such as schizophrenia. Hallucinogens produce changes in perception, thought, and feeling, ranging from distortions of what is sensed...
  Encyclopedia Britannica
  Encyclopedia Britannica, Inc., 2020