I got ADD aswell and I am taking methylfenidaat. My doctor said that I shouldnt take this medicine after 4 pm because it can prevents me from falling asleep in the evening. But one day I took an afternoon nap after consume the medicine because I was tired. What happened afterwards was kind of funny. I started to have dreams, then I quickly wake up. But my body is completely in sleep paralysis so I cant move at all. I didnt know it was sleep paralysis, I thought it was because I was laying on my blood vessels. After ten seconds I can move again. Then I go to sleep again, got another dream, wake up again and got myself into sleep paralysis again. This happened 5 times in a rowl lol, it was probably the first time I ever got SP. So yeah, medicine can have some effect on your sleep. I was thinking of using this medicine to do WILD, because I cant seem to reach the SP stage normaly. but I dont know if it may have any negative effect so I didnt try a second time .