Has the doctor been told of the side effects? They can't do something if they have no idea it's happening
Voices aren't part of the side effects of adderall. Agitation can be. The closest thing in taking too much would be paranoia - which does happen at too high a dose with almost all.
Most likely your niece has some other problem (like bipolar disorder) that can look deceptively like ADHD but reacts poorly to ADHD meds.
I would recommend she get sent to a pediactric psychiatrist who specializes in this kind of disorder - so she can be checked for alternative problems. It sounds like this doctor is not fully versed in ADHD so probably is just going by trial and error. And definitely make SURE that they know what the side effects are - most likely they'll have her drop the meds ASAP.
Thank you for the advice. I will show my sister these messages and hopefully she will tell the dr so she can get off adderall asap. My sister is willing to try a natural product for ADD that I read about on the boards so I will be getting a supply of those supplements for them too.
I would definitely talk to the doc about these side effects ASAP. Some people hallucinate on the meds--perhaps the voices are a side effect. Also, going on no sleep will just make things worse. You say she's talking non-stop. Was she like this before meds as well? If not, that's a definite sign that she shouldn't be on Adderall (or at least the dose she's on).
You also say that she's showing signs of anxiety and depression....TELL THE DR.! People are often misdiagnosed with AD/HD when they actually have anxiety or depression (or a combination thereof).
I would be tempted to go to a different dr. Getting a second opinion might be the best idea in this case (for proper diagnosis and medication management if needed).
Good luck and keep us posted!