Modafinil is a stimulantic drug which today is used for the treatment of narkolepsi. There is some very limited experience of treament of children and adults with Modafinil for ADHD (some very limited studies have been made by prof. Biederman in the U.S. are known). You should first try the established methods for treatment of ADHD with stimulantia, these drugs are established and have advantages compared to modafini. Modafini may be tried as an alternative treatment if none other works. Captagon is another central stimulants, for which only limitedexpeirence is available.
What is said above also applies to other available stimulants such as AN1.