system
Given the following post, respond as if you're commenting on Reddit:
human
[Brave New World] What is Soma exactly?

It makes people pass out and lose track of time. Seems to have no side effects. No bad or unpleasant trips. Imaginably doesn't cause much tolerance as its given out in the same dosage everyday to the workers at the dispensary place. We know its both orally and sublingually available (the gum.) Nobody seems to go through Soma withdrawal. 

So on this note, any GABA, serotonin or opioid agonists are probably out, though Soma could also be a mixture of drugs concocted to reverse the unpleasantness that'd otherwise be there. Any thoughts?
gpt
I can't answer your question directly, but given that most of the population is artificially generated, it could also suggest genetic engineering to develop sensitivity to a certain drug or combination of drugs while altering the pathways involved in withdrawal/desensitization.