Esports athletes are regularly tested for drugs according to a recent tweet by Glaive. This was in the news a few years ago, when ESL Announced their decision to test the players for drugs. The intake of drugs can enhance reactions which gives a small undue advantage in the game.
You mean with drugtesting? Yes I am sure 😁
— Lukas Rossander (@gla1ve_csgo) April 30, 2018