All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the student is not in need of using such medicines, then he should not use them because they might lead to some harm. In addition to this, there are many other means which help in concentrating and strengthening the memory, some of which are mentioned in Fatwa 90456.
However, if he needs this medicine and using it does not lead to any harm, then it becomes permissible for him to use it but he should consult the specialists in that field because it is not permissible for a person to use what leads to harm.
Allaah Knows best.