Certain stimualants, for a short time until you get paranoid. Opiates and Benzo's do it for most people. I never have had a problem myself talking to people or being socialble, in fact I'm the opposite, especially in a state I'm visitng, no one knows my past or judges me based on it when I leave my area. I can easily "read" a stranger, mostly older 40-60 year old people and tell if they are cool. guess that comes from growing up around older people in the "drug scene" like family and thier freinds.
I can relate to those my age or older very easily normally, and if I am on opaites or Xanax or something like that, then I approach strangers in other states I visit to just BS, and often end up getting a free buzz that way or offered some kinda drugs..lol.
I am told by some that I have a dope radar in my head ,becasue I seem to always make friends or whatever with people that turn out to be weed smokers, speed users, opiate users, etc. in a state I visit for the first time or 2nd and I meet someone and 1/2 hour later I am getting high by them and usually getting offered some drug..lol.It's both cool and a curse(if I am trying to avoid drugs it's a curse almost..lol).