Modafinil was studied for the treatment of stimulant dependence, but the results are mixed and inconclusive. Modafinil is not a controlled substance in some countries, unlike other medications, such as bupropion, which is also used to treat depression and nicotine dependence. The clinical trials that have tested modafinil as a treatment for stimulant abuse have failed to demonstrate its efficacy and the optimal dose and duration of modafinil treatment remain unclear, and modafinil is not a recommended treatment for stimulant abuse.