NOT A REF AS SUCH BUT WITH STRONG OPINIONS ON DESIGN ELEMENTS INVOLVED
I always assume that the Kallavesi mystics have been getting fucked up on drugs since time immemorial. My only caveat is that their drug induced trances did not reliably result in visions of auras, or symbollic magical vision quests revealing plot points relevant to the weekend. That’s what a potion/ritual/ribboned drug is for because it goes beyond roleplaying into an area of mechanics. Want to RP taking mellifluent rhind and hearing the harmony of the spheres? Go for it … just don’t try to use that RP to gain a mechanical effect*.
I personally see no problem at all with RPing taking drugs - the problemsfor me start and end with:
- “Forcing” and RP experience on someone else
- Mechanical advantage/disdavantage.
A bunch of Wintermark warriors can get together and mix reindeer piss and mushrooms and talk about the spirit of the beast coming on them to their heart’s content - it’s just girding or marshalling by another name. They can even mix their pre-battle drug ceremony with some Tinctures of the Deep Forest to add additional validation.
Likewise, I don’t expect anyone to have to spend Marrowort to treat their mate’s IC hangover - unless that hangover is the result of a poisonong or curse, at which point there will 99.9% certainly be a method of removing the effect that has a cost.
Heck, we don’t expect people to lammy their chocolates or oysters even though they are apparently aphrodisiacs 
About the only place it’d cause me any problems at all would be trying to use recreational drugs as an excuse for a variant response to a roleplaying effect, or where someone tries to use roleplayed narcotics as a way to pressure someone else in a way that (effectively) duplicates an RP effect … which are about influencing your character rather than forcing/mandating responses.
So … if Joseph or Josephine Marcher joins your reindeer-piss-and-mushroom circle prior to a battle, and wants to RP being a bit drugged up thats cool. If they don’t, then they either didn’t swallow or didn’t get a full dose or are just naturally resistant to reindeer piss.
Poisoning falls in the same category. While IC I could slip someone some poison mushrooms, I would want to be careful about PD approval for forcing RP on someone else, especially one that has a “cost” to deal with - albeit the minor cost of 1 mana. Much easier to just pour some gutwrench into their pint with the aid of a referee.
At the point where you blag some magic herbs out of a Spring eternal, they do what they say they do - likewise, at the point you get some of that cool spore-infested-human-meat drug the Sarcophan make, it does what the rules say it does.
We’ll almost certainly never lammy “random narcotics” and more than we lammy random booze, sweets, baccy or asprin. Or bandages, surgeons rools, disenfectants, firelighters, lightstones … as long as its just an RP prop, we’ll treat it as such I think.
Although we might disgree with you as to whether it is just an RP prop or not 
- And I say this as the man who will, three days later, be trapped in a six hour conversation with the Boss when someone who doesn’t realise what is going on sends an angry e-mail about how so-and-so clearly has a special power that lets them hear the music of the spheres that lets them cast detect magic without using mana, and demanding the ability to duplicate that power.