Tough call. You'll probably never know if it fixes a legitimate disorder or if she manipulated her way into getting it. Th former in which case it wouldn't be a "drug", but a "medication".
Simply knowing her line of work doesn't mean she got the prescription by fucking people.
I agree that she should be able to provide proof, maybe a letter from her doctor, that they are hers...come to think of it, no one has asked this but maybe because we all thought its way too obvious, but is there a label on the bottle with her name on it?
Even if she didn't have narcolepsy or whatever before taking hard stimulants, if you take them, she's going to have nasty withdrawal symptoms reminiscent of narcolepsy and such. She may not even be able to get another prescription.
If she does legitimately need them apart from not going into withdrawal, you would probably be taking away her ability to work at least for a while, and that line of work is horrible anyway. Her doctor might refuse to continue prescribing it. She could lose her job. She could resort to buying meth on the streets...