"The terms entactogen and empathogen are used to describe a class of psychoactive drugs that produce distinctive emotional and social effects similar to those of MDMA. The term "empathogen" was coined in 1983 by Ralph Metzner to denote chemical agents inducing feelings of empathy. "Entactogen" was coined by David E. Nichols as an alternative to "empathogen", attempting to avoid the potential for improper association of the latter with negative connotations related to the Greek root "pathos" (suffering).
Nichols also thought the word was limiting, and did not cover other therapeutic uses for the drugs that go beyond instilling feelings of empathy. The word "entactogen" is derived from the roots "en" (within), "tactus" (touch) and "gen" (Greek: produce). Neither term is dominant in usage, and, despite their difference in connotation, they are essentially interchangeable, as they refer to precisely the same chemicals."
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More Info...
- Brain mechanisms of hallucinogens and entactogens
- Differential Actions of an Entactogen Compared to a Stimulant and a Hallucinogen in Healthy Humans
- Entactogens @ Drugs Forum