There's a few reasons why Adrafinil isn't scheduled. It wasn't ever approved by the FDA or marketed in the US and never used heavily in the US, thus the DEA never bothered to regulate it. When Modafinil got FDA approval, the DEA felt the need to evaluate it.
Adrafinil was used in France and other parts of Europe, however Cephalon is no longer allowed to market the drug in France, and they have discontinued it.
