Wow. I am 55 and just got very serious about golf after being a 2 times a year golfer for years. I took some lessons and became a devoted student of the game. I practice like mad - short game, long game, all of it. I am also ADHD, but out of meds (ritalin). I wasn't seeing improvement in my scores like I thought I should see. I was shooting high 40s, low 50s on 9s but in practice was hitting gorgeous shot after shot.
Then I found an old prescription of ritalin and took some before my last 4 rounds. OMG!!!!!!! My pinball brain became calm. I started to strike the ball well consistently. Approaches were hitting greens and my putts started falling. And my scores? It is absolutely dramatic. I am now shooting low to mid 40s past 4 rounds. I am hitting greens, making pars and most importantly, not falling apart and letting my pinball brain take my game away from me.
I don't believe ritalin is considered performing enhancing if it is prescribed. Not sure. It shouldn't be. My doctor always told me that for an ADHD person to take ritalin is like a near sighted person wearing glasses. It brings the world into focus.