I went to university at a time that Adderall was commonplace, and am now old enough to see how it turned out for the individuals. At college, it was common for students to illicitly purchase Adderall to use as a stimulate to cram for a test/paper etc. It was likewise common for students to abuse these drugs by taking pills at a faster than prescribed pace to work for 48 hours straight amongst other habits.

In the workplace, I saw the same folks struggle to work consistently without abusive dosages of such drugs. A close friend eventually went into in-patient care for psychosis due to his interaction with Adderall.

Like any drug, the effect wears off - Cognitive Behavioral Therapy matches prescription drugs at treating ADHD after 5 years. As I recall, the standard dosages of Adderall cease to be effective after 7-10 years due to changes in tolerance. Individuals trying to maintain the same therapeutic effect will either escalate their usage beyond "safe" levels or revert to their unmedicated habits.

In my experience, Adderall does lose effectiveness but Vyvanse is much hardier. I’ve been receiving treatment for ADHD for about 4 years. My current Vyvanse dose is marginally higher than my original Adderall dose, but I’m considering reducing it down to below my original Adderall dose.

Cognitive behavioral therapy does excel at treating ADHD! But 5 years of therapy is what, 16 times more expensive than 5 years of medication? Maybe more? Not to mention the time commitment.

The person you're replying to asked for a source, not an anecdote.