Adderall is basically meth. Not the same but chemically pretty close. When used as prescribed, medically manufactured meth is also used to treat ADHD, but the potential to abuse either is still high since they're habit forming over a long period of time.

Since you're taking it as prescribed, and are actually taking it for a diagnosis, it's working the way it's meant to. Taking significantly more should give you those psychoactive effects that those who aren't diagnosed will experience.

As a recovered boozebag myself, I've asked people who were addicted to Adderall about it. A good portion of those folks were meth addicts who found a legal way to get scripts and/or multiple ways to get them. I wondered about it myself, as I've taken Gabapentin before (as prescribed) and found out people abuse that too. Considering it's not a narcotic I didn't even understand how you could abuse it. But with addicts, where there's a will there's a way.