In canon, Gamzee eventually shows another personality (or, perhaps, even two other personalities) that surface after a series of events. In order to keep his other personality under control he has to constantly take any potion that will numb his mind (akin to the sopor slime of his canon, which is normally used to help trolls sleep and isn't meant to be eaten), almost like getting him high - another basis from canon. I'll be describing both personalities in this section, and, for sake of convenience, will be referring to his numbed or drugged state as high.