[Trilkhai]

Soma in BNW is described in a way that matches a combination of opiates and hallucinogens -- it artificially elevates mood, makes everything seem wonderful and pleasantly exciting, causes sensory hallucinations similar to synaesthesia, and so forth. That's a whole world away from Xanax, which merely controls anxiety & nausea with a side-effect of feeling sedated.

[dfrage]

And Soma wouldn't be useful in pacifying a population if it induced tolerance in a few weeks like Xanax and the other GABA influencing drugs do.