Long term effects of Vyvanse on memory and other brain functions

[omlet]

Extreme fatigue, improved only by vyvanse.
Must use 70mg three times a day to decrease
fatigue and improve mood adequately.
Question: What are the long term effects of vyvanse
on one's memory and other brain functions?
(And have there been any well constructed studies done on this subject?)

This is an attempt to "Ask an Expert".

[caregiver222]

You can go to the FDA site and e-mail or telephone for the physician who is responsible for the drug. Use the generic name. At the FDA every drug is assigned to a physician investigator. Once you get his name e-mail him. If you don't waste their time they are quite helpful. If you feel this side effect has happened, you need to report it as a "possible adverse effect". Then ask him/her if there have been any other reports. Another database to search is Pubmed. That being said, I researched the drug and there doesn't appear on the surface to be interactions that should cause permanent loss of memory.

[omlet]

I now see how to "ask an expert" involves a fee.
Makes one feel a little misled.