Although it should work the same, it doesn't always depending on how sensitive the person is. My son had that problem with generic ritalin, and I've actually read that somewhere as well- wish I could remember where.
You could always try something else.
I too am sensitive to the differences between real and generic Adderall. By far I prefer the real McCoy!! I've picked up three different "generic varieties" at the pharmacy over the years... a funny tiny 10 mg white "pillow", the orange, oblong 20 mg pill and the rosey-red round 20 mg. pill. BIG difference between the red and orange pills for me, so now I call ahead and make sure I get the orange guys. I recently tried getting name-brand Adderall IR but the cost was out of this world! I was told it was so high 'case Shire really wants everyone switching to Vyvanse, since that's got many years before it's patent runs out.
I was on adderrall 30 mg for about 8 months before Shire outsourced it to Barr and since then it has never really had the same affect . I have attempted to try the XR and have found better results but it still is not anywhere close . I 'll be seeing my psychiatrist in a day and I'm not sure how to present this dilemna .It makes you wonder how something that worked so well could just totally change .Has anyone else had this problem ?