Aldous Huxley predicts Adderall and champions alternative therapies

I read champignons and it kind of fit even better. Adderall (Brave New World) and mushrooms (Island).

Soma in BNW is more analogous to MDMA as it's about sedated pleasure, not mental clarity/performance.

I seem to think marijuana is more about sedated pleasure than MDMA. Granted, it's been about 30 years since I read Brave New World.

I'd say something with the intensity of weed (relatively low) along with the effects of MDMA. Essentially "MDMA lite"

Marijuana often seems to promote thinking "outside the box" which is probably not what the Brave New World people would want for their population

I think he was inspired by Valium and other benzos. They put people into a docile, low-anxiety state, and they were popular around the time the book was written.

That's also more-or-less consistent with the implied literary reference to the Lotus Eaters, who I think are usually imagined as opium users. Opioids are different but are also downers that reduce anxiety.

Benzos later featured significantly in one of Adam Curtis' film-essays -- maybe Century of the Self, maybe another one. I'd view those films as being in a similar spirit to Brave New World.

If we are talking about BNW, which was written in 1931, then that book predates benzodiazepines by 25 years or so. Perhaps you are thinking about barbiturates?