Self medication is a massive problem for college students with ADHD because so many university clinics refuse to prescribe stimulant medications, even to those with a previous diagnosis and history of responsible medical use.
When I was a broke college student, there was not a single provider in my healthcare plan that prescribed them. All they did was aggressively push worthless non-stimulant medications. I would have had to spend over $500 out of pocket to get the one pharmaceutical that I know has always worked for me, but had no disposable income. I didn’t self medicate, but still barely survived undergrad with untreated ADHD. It took me an extra year and a half to graduate because of it.