Modafinil the popular drug for narcolepsy has a long history. It was born when Adrafinil a stimulant drug was developed to treat sleep disorders, narcolepsy.
The main plus point of Adrafinil which was developed in the seventies by a French company Lafon laboratories was the absence of any type of serious side effects like anxiety or recurrent behavior and its users did not get addicted to it.
The short coming of Adrafinil was that it took a long time to show its effects because the body had to metabolize adrafinil and create a new substance which works as stimulant. The French company Lafon Labs decided to market this metabolite as a completely different drug which was named Modafinil.
source- www.modafinil-tablets.com