That's probably one of the things he uses. But I don't think it's the only one. He doesn't display much syntoms of coke use, but rather some kind of opium thing (heroin, morphine, etc.). He probably does more than one thing. One to balance out the other. Who knows!
"...whatever is true, whatever is honorable, whatever is right, whatever is pure, whatever is lovely, whatever is of good repute, if there is any excellence and if anything worthy of praise, dwell on these things." Phil. 4:8