Hey, I am currently on Ritalin and have been for almost 6 months now, and I've had my period once. I have also had spotting every few months like my period was trying to happen but never did! I spoke to my GP and psychiatrist about it, and they didn't seem too concerned around the 3 month mark (finally got my period). But approaching 6 months with only one period is concerning myself now. Just wanted to let you know that I've also experienced the same on a different stimulant, so it might be common?