I'll use GGGB as an example. I was ok with Ash doing coke, until she became addicted, because I'm not a fan of drug addiction. I know that sounds like I'm trying to have my cake and eat it too, but I find the fantasy of drug use far more thrilling than the realities of addiction. I dated a girl that became addicted to pain killers, she started getting into self harm so that she could get doctors to prescribe her more medicene. Addiction is not a fun reality, and for me it's not a fun fantasy explicitly because of how close it touches reality for me. Ash / Lena doing drugs to have a more fun at a party, fun times. Ash / Lena getting addicted to drugs and knowing how life ruining that is, not fun times.Maybe; but on the other hand, it also costs a will point to take the drug when offered for the second time, if Lena refused it at first. So this isn't directly related to any addiction.
Having to spend a will point is already a harsh price, given Lena who tangled herself with Axel and/or Seymour might have just one or none at all, so i don't feel like it's something that needs an escalation. On the other hand, it wouldn't be unreasonable to presume a player who already had Lena take drugs twice isn't really interested in making her stop, so there's no point in asking them again. Guess we'll see, it's all theoretical at this point anyway.
So once I know where the line of addiction is for Lena, I won't cross it. In all of my many playthroughs of GGGB Ash only got addicted the first time.