Follow-Up: I HAVE BEEN ON PROVIGIL FOR ABOUT A YEAR. IT DOESN'T WORK AS GOOD AS THE CYLERT THAT I WAS ON FOR 7YRS. ALSO IT IS REALLY EXPENSIVE 297 PER MONTH. I TAKE 2 200M PER DAY. SOMEDAYS I AM NOT SURE IF I TOOK IT OR NOT, BECAUSE THE RESULTS AREN'T THERE. I THINK IT MIGHT WORK FOR PEOPLE WHO WANT TO STAY AWAKE THAT DON'T HAVE A SLEEP DISORDER, BUT SO FAR I AM NOT IMPRESSED.