The main difference between Adderall and Vyvanse is that Adderall is a mixture of four different kinds of amphetamine salts (one of which is dextroamphetamine) while Vyvanse only contains one type of amphetamine salt, called lisdexamfetamine. Lisdexamfetamine gets converted into dexamphetamine once it is in the body. One advantage of Vyvanse is that it may be less likely to be abused; however, there is no generic form available so it is more costly than Adderall. Because both drugs contain amphetamines, they work in a similar way. Studies have shown that Vyvanse is just as effective as Adderall, and side effects, including the risk of dependence, are similar.