If this is widespread and a big fetish as you say, then it's got to be amateur because both a producer and a director at one of the big studios would not allow a girl to be "wacked out" in her scenes - it leads to big insurance risk at where they shoot. Liability falls both with the producer, the director and with the studio. Imagine someone getting injured or hurt while stoned. Or the other performer getting hurt because the other person was not being responsible. Most model releases that porn actors and actresses sign before shooting say, "that the performers have to be stone cold sober." If they show up wrecked, then they can't perform. Plus if it's hardcore (b/g), most times, the performers would not be able to have orgasms. Guys especially would not be able to get hard much less ejaculate with alcohol and many drugs in their systems.