Purdue Pharma will likely see 10B+ in settlements brought against them in the coming years for their hand in marketing Oxycontin as non-addictive.
On the topic of Ritalin and Adderall, lots of my friends found they had to increase their dosage to see consistent effects. Some talk about abusing alcohol to get to sleep. All have told me interesting stories about being able to "feel" their heartbeat in odd ways while using (or over using) it. I'd be surprised if both drugs don't see significant settlements related to heart issues, alcohol dependence, or something else in the not too distant future.
ADHD exists. Period.
Also, US history has a bend toward over medicalization and over prescription. I think it's important to learn about this and weigh it when using any prescription drug, but especially highly addictive ones, for extended periods of time.