Question:
This was buried in another thread, so I am creating a new thread so it will be more prominent. Some DXMers might find this as a fun way to prevent the brain damage. Although, the question would be are the doses one would take of LSD with DXM enough to prevent possible damage? Also, interesting to note that one thing this study suggests is "It is proposed that 5HT2A agonists may also prevent the psychotomimetic effects of NMDA antagonists." If so, then LSD would itself alter the character of a DXM trip.

Answer: Based purely on guesswork/intuition, I think an active dose of LSD would be enough to block damage from a reasonable dose of DXM. This is "based" on the idea that the damage caused by DXM (if any) must not be huge since we don't hear a lot of reports of problems, and that LSD is a pretty potent agonist at these 2A receptors. Based on trip reports using both of them, it seems unlikely LSD actually blocks the effects. But the lack of blocking the mental effects may also be evidence it does not block the damage, either.

Based on the anecdotal data I have of recreational DXM users, which relatively speaking is fairly extensive, it takes some effort to fry your brain with DXM. YES, I believe it happens. However, all cases I know of I believe are suggestive of possible Olney's lesions with DXM involved high dose use (upper plateaus), and also done very frequently, as in at frequencies most would call serious abuse. And, none of these people reporting possible brain damage took any precautions, like using drugs that in theory would prevent brain damage. IMO, LSD seems to be a reasonable candidate as a drug to prevent Olney's lesions, based on theoretical considerations. However, LSD + DXM at higher recreational doses is reported to be "one hell of a trip". This ISN'T the sort of thing someone should do without a sober trip sitter. Or, by anyone who is unwilling to take the risks of a serious "journey to the center of the mind" trip. This sort of trip is NOT for those who may not be able to handle temporary total psychosis. LSD may prevent permanent brain damage from high doses of DXM. However, consider well if a that not only may LSD be "pretty potent" at receptors that will prevent brain damage, but also the possible consequnces of a trip this "out of this world".