Weird, never heard that one before - and I have been on this site for 4 years. I think that a lot of the adults with ADD would be real surprised if it were true. As long as you have a prescription you are fine.
I'm on adderall and just started last fall and I am 44 years old. So I would say someone is giving you misleading info. Again, as long as you are on a prescription and it seems to do the job, then there's not reason not to take it after you are 18.
I'm 25 and just got diagnosed with ADHD and got put on dexamphetamine...i have spent months and MONTHS researching the disorder and i can safely say that what this person (who ever they are) told you is a bunch of HOOEY! (quoting dr phil :P)
ADHD doesn't just stop at a certain age....it continues into adulthood! Even though by this time some of us may have developed coping mechanisms in dealing with the effects ADHD has on our lives.
I too am studying...(i'm going to be a drug and alcohol worker!) and I have only been on the ADHD meds for just over a month and there has been a MAJOR change in me...in every way...
It is NEVER ever too late to go on medication
That's too funny. Get back on your meds and have a successful life!!