Yes, when ADHD sufferers get locked in, they are like pit bulls.
In 2006 there were 28 major league players who had diagnoses for ADHD, and were receiving treatment withstimulant medication during the season. Theywere permitted to receive such treatmentwith stimulants through MLB's "TherapeuticUse Exemption" program.
Then, players got wind that ritalin helps your game, so the number of players that had ADD surprisingly went up lol
You can still use ritalin, etc. in MLB, however, you need to prove yourself to not just doctors, but MLB, you pretty much have to jump through hoops to prove you need the drug.