Psychoactive Drug
From Star Trek : Freedom's Wiki
Psychoactive drugs are chemicals or herbs taken internally for use in spiritual journeys or for abuse. Some psychoactive drugs facilitate hallucinations or altered states of consciousness.
Chakotay revealed to Captain Janeway while showing her how to reach her animal guide that his tribe used to use psychoactive agents to achieve their vision quests in an attempt to reach their respective animal guide. Chakotay noted that they discovered a technological means to achieve the altered state of consciousness. (VOY: "The Cloud")
One example of a psychoactive drug is LSD.