I take Modafinil. Prior to taking it, I did not function very well in the mornings. If I slept 6, 8, or even 12 hours, it still took forever for me to become alert in the mornings. I could not take early morning classes because I wasn't alert enough to pass them. With Modafinil, after about 20 minutes of the usual morning grogginess, I am a normal human being. I have no trouble getting to sleep at nights either. As for side effects, impotence occurs among some users. After getting through the first couple of weeks, I felt no side effects. I am working on my PHD and noticed some effects relating to my cognitive abilities. At first, my dose was too high and I felt mentally sluggish. I second guessed myself much more than usual in classroom discussions, usually resulting in me remaining silent. Once I lowered the dose, I felt slightly sharper than normal, but not foolishly overconfident as in the case of speed. Some people claim the effacy of the drug declines with use and recommend taking a short holiday from it. I did that last week because I was out of school for the holidays and had no pressing need to be up at the crack of dawn and mentally sharp in any classes. I have suffered no withdrawl symptoms. The only thing I have noticed is that I have returned to my normal sluggishness in the mornings. That being said, I think those who tout it as a smart drug are stretching the truth. Feeling smart and actually performing well are two different things.
Drugs in the same class as Modafinil usually interfere with insulin secretion and raise blood sugar levels. I just wonder if Modafinil does the same.
p.s. What are you getting your PHD in?