it's extremely hard to find info on it in English (the main hits are all... from the Disco Elysium dev blog, lmao)

Taren was a drug that was issued to Soviet soldiers as a purported medicine for radiation poisoning! the chemical name is aprofine.

anyway it turns out if you didn't have radiation poisoning and took them it would make you absolutely fucked up

when the Soviet Union withdrew from Estonia they left behind a massive stockpile of Taren which then made its way onto the streets and became very commonly used because it was so cheap, though it was never very much liked because it is not a psychedelic but a deliriant

bit of hallucinogen info here: there are four types; classical psychedelics, dissociatives, kappa antagonists and deliriants

classical psychedelics work by pretending to be serotonin, blocking transmission of thoughts through your most streamlined brain routes (the Default Mode Network) and forcing your brain to compensate by using weird alternative routes to send signals.

so you remain basically conscious, the hallucinations you see are distortions of existing reality, and the real interest is in these new thought connections which tend to be euphoric and profound (or the worst experience of your life, but a profound bad experience)

these are the psychedelics most people think of, like LSD and mushrooms

the dissociatives shut down a different part of the brain that creates a feeling of things being "unreal", which is usually less profound but also less likely to go totally wrong, so they're more suitable as club drugs. Ketamine is the main dissociative people tend to use

the kappa antagonists are a weird one that not a lot is known about but they work by disconnecting the part of your brain that processes your consciousness from your sensory input. they are known for producing very short-lived and intense out-of-body experiences where you are catapulted into a completely incomprehensible alternate dimension. salvia is this

the deliriants poison you and make you go temporarily insane.

deliriants are basically recreational fever dreaming or extreme sleep deprivation. people see totally realistic hallucinations indistinguishable from reality, and usually of things that are at best pointless, at worst utterly horrible.

speaking to inanimate objects is a major theme. talking to a friend and then realising the friend is not there. deliriants are also notorious for making people revert to primal states like taking off their clothes and shit. and on top of this, they also ruin your eyesight

the most famous deliriants you'll be familiar with are, like... deadly nightshade. belladonna. atropine. the pupil dilator

this is because deliriants inhibit acetylcholine receptors, which is medically useful because they are involved in a bunch of processes like inflammation, pupil dilation, nausea... all stuff radiation poisoning does to you

but that's also a pretty good way to kill you. Taren appears to have been relatively safe, but other stuff will absolutely wreck your shit, like datura, a plant which is totally capable of causing you permanent vision damage at minimum

Taren was notorious for causing inability to sleep, which is also something associated with pyrholidon in the game

however... this is where it gets a bit more confusing, drugs never just do One Thing in your brain, your body is way more subtle and interesting than that

for example, cocaine is primarily an anaesthetic but it has strong stimulant "side effects" and also some weird deliriant activity, which is why 1) it's traditionally used to treat nausea, 2) people who do too much cocaine are really prone to start seeing spiders all over the place

some of the real world deliriants which have a reputation for being more enjoyable than others similarly have a combined profile. nutmeg is a combination deliriant and cannabinoid, so it's a lot gentler and more giddy than the main deliriant people abuse, Benadryl

fly agaric also has a reputation for being comparatively entertaining and that is a combined deliriant/downer (similar to benzos)

the other one that is considered to be less horrible is a particular drug I can't remember the name of which is used to treat Parkinson's, so it combines a deliriant with a dopamine-releaser. dopamine makes you feel excited, euphoric and stimulated.

soooooo, back to DE:

this explains a lot of the weird shit about pyrholidon, such as the weirdness of a psychedelic that helps with radiation poisoning, but also its strange effects. however, at least according to Electrochemistry, pyrholidon feels "warm" and lovely. deliriants, uh, do not conventionally do this!

however this DOES explain why the kind of visions Harry has on pyrholidon are of the apocalypse

and of talking to inanimate objects, of course

maybe pyrholidon is a deliriant with some opioid effects? that would explain the feeling of emotionally numbed cosiness and also be useful for treating pain

this can also explain why pyrholidon doesn't appear to give Harry any visuals - people on deliriants don't usually think they are experiencing visuals or in a particularly interestingly non-sober state at all until a hideous zombie crawls out of the bathtub

(another reason why they are dangerous - people think it's not kicking in and redose, and these substances tend to be extremely poisonous!)

some of Harry's weird experiences make sense if you assume he still has large quantities of a weird deliriant in his system, like the light bending guy