Swim has been taking vyvance for swims ADD for at least 3 years with brakes during summer time.Swim doesn't see why swims not addicted after that long. Is it possible for you not to be able to get addicted to amps.
Yes it's possible that you're not addicted at all after 3 years near-daily use of Vyvanse. There's no real physical addiction with stimulants. Some people can develop a psychological dependency, get cravings, particularly for shorter acting stimulants, but they wont really get sick if they stop like somebody addicted to downers would. Vyvanse (lisdexamphetamine) should be less addictive than plain amphetamine because of the slower release & extended duration, if you've stuck to using it as prescribed it's fairly unlikely you will develop a problem with it.
This doesn't mean that you couldn't possibly get addicted to amphetamines. Taking low prescribed oral doses of a mild extended release amphetamine is very different to smoking or injecting lots of meth.
I took Adderall in low doses the way the original poster did for ADD for about 2 years, with a break during the summer, or when I was not in school like on the weekend or during holidays, and I did not get addicted to it.
I hated stims soooooo much and took them on RX for 2 years when I was in high school. When I got off them it was the best day of my life. No WDs just felt SOOOOOOO much better.