Sigh. Can you cut out the "prescribed drugs are bad because they must be bad" bullshit?
ADHD stimulants absolutely do not work as _enhancers_, as your article explains. But they are not used as enhancers, they are used as medicine to fix problems. As another example: vitamin C does pretty much nothing normally, but if you have scurvy, it's life-saving.
Here's an important quote from your article:
ADHD undergraduates are capable of performing just as well in college as their non-ADHD peers, if they acquire well-established effective study habits
Which basically says: "ADHD drugs are not needed if you can fix all the symptoms of ADHD without drugs". Well, duh.