The Electronic Sports League professional gaming organization adopted a list of banned substances compiled by the World Anti-Doping Agency, according to a Reddit post this week.

"Our main goal is and always will be to maintain the fair play spirit and the integrity of our competitions," the post reads, "and we're confident that the anti-doping policy is an important improvement that will help us advance as a sport. It is a small, but in our eyes essential and meaningful step forward for professional gamers across all games, ESL as an event organizer, and the esports industry as a whole. There were a lot of questions left unanswered since the first announcement, and today we're ready to share more information with you."

The ESL's announcement followed Kory "Semphis" Friesen's admission last month that the professional Counter-Strike: Global Offensive player used Adderall during the ESL One Katowice event in March. Adderall is a stimulant typically used to treat attention deficit hyperactivity disorder (ADHD).

"We were all on Adderall," Friesen said in a video interview. "I don't even give a fuck. It was pretty obvious if you listened to the comms. People can hate it or whatever."

"We were all on Adderall. … People can hate it or whatever."

The ESL will test randomly and make exceptions for banned substances for which competitors have a prescription, like Adderall. Before the start of the first match, competitors will be required to provide proof like a letter from a physician "that they need this specific medication."

According to the World Anti-Doping Agency's official site, banned substances include marijuana, the use of which the ESL will prohibit "from the start of the first day until the end of the last day of competition," anabolic agents like steroids, growth hormones and more. WADA prohibits the use of some substances at all times, others during competition and still others only in particular sports.

Testing positive could result in a range of punishments from reduced prize money and tournament points to disqualification and a maximum two-year ban from ESL events.

While the ESL originally planned to perform skin tests, it "came to the conclusion that saliva tests are better fit.

"Tests will be performed at our discretion at any time during tournament days, and will take place in a designated testing area. Naturally, player's privacy comes first."

The ESL announced its plans to implement the anti-doping policy late last month.