I was diagnosed with Shiftwork Disorder at one point in time and was prescribed Modafinil and it was incredible for the most part and had zero side-effects, but my doctor wont prescribe it for ADHD. One down-side to Modafinil is that I could get stuck on an unproductive task and would realize in hindsight that I had just been hyper-attentative to this unimportant task for hours.