I don't know about any studies that have been run, but I doubt that any conclusive studies have been done. The problem is that most anti-depressants build up in your body so that someone on anti-depressants is on an effective dose all of the time. The medications used to treat ADD/ADHD last under eight hours effectively and follow a standard distribution curve. Personally as someone who has ADD and is bipolar I strongly suspect they do. All of that distractability, the rapid loosely connected thoughts, the decreased inhabitation in ideas can lead to intense creativity in the right circumstances. By the increased ability to focus on one thing at a time and decreased environmental reactiveness I am sure you lose some of that creative potential. You gain a great deal of ability to get things done though. And its creative potential not creativity so by being on meds you lose a lot of not very useful daydreaming and gain the ability to focus on what you want to focus on. Hopefully that was of help.