I posted a message yesterday, and i believe i wasn't specific enough about my problem. I am currently taking risperdal for schizophrenia, and since i have began taking it, I am fatigued all the time. I didn't know if it was CFS or just from the risperdal, so i went to a doctor. He told me that it is from the risperdal, and prescribed me provigil to combat it. I have been taking it for 3 days and really haven't felt any better. I was wondering if provigil is like SSRI's in the way that it has to build up in your system for it to be effective. Or does it start to make you feel better about an hour after you take it. I am curious because if it doesn't have to build up in your system, I am going to call my doctor about it. Thank you for responding.