At least in Australia it seems a bit harder than just reciting symptoms. You have to get family members involved for interviews, past school results, etc to prove it because the government really doesn't want everyone getting their hands on the drugs.

I really don't think most people could fool an experienced and diligent professional, emphasis on diligent. An assessment should be more than a box ticking exercise where the patient is just asked to recite a list of symptoms without any further inquiry, especially for students who present a higher risk for feigning symptoms, but I don't know how rigorous the testing really is in the US.