That's a high dosage, to the level where I expect it is neurotoxic. I think you might be more of the exception than the rule... some withdrawal is to be expected, though not necessarily as strong as OP.
56mg means Concerta, which is an all-day extended release formulation - not the same as injecting 56 mg into your mainline, or taking an immediate release tablet.
Concerta wouldn't come in a 56mg tablet if it was expected to be neurotoxic.
Good point. As he was responding to someone discussing amphetamine, I thought he meant amphetamine. I have known someone prescribed 3x20mg short acting amphetamine daily who after stopping is now quite aware of the long term negative effects.
High dose stimulants in rats are neurotoxic. http://www.dr-bob.org/babble/neuro/20091104/msgs/931964.html Your mileage may vary, but I think prescribing patients >50mg amphetamine is often irresponsible. Ask your psychiatrist at what dosage he thinks amphetamine is neurotoxic. 90mg maybe? Doctors agree that a certain dose is neurotoxic but disagree on what that dosage is. 60mg is the official maximum safe dose, but it's not like you should put all of your trust in the FDA. Given clear stimulant burn-out I have noticed in multiple taking >50mg of amphetamine daily, I have no doubt that dosages like that cause negative neurological effects and that caution is merited in amphetamine dosing.
Stimulants aren't neurotoxic, specific substances at specific levels are. Methylphenidate's majority of benefit comes from its reuptake inhibition of both dopamine and norepinephrine. While it is also a dopamine releasing agent, it does so at dramatically lower levels than the amphetamine family. The difference turns out to be significant - while they both promote more dopamine activity in the brain, it turns out that preventing the disposal of brain chemicals is generally much safer than promoting their release. As far as I know there aren't real concerns about MPH neurotoxicity.
Methylphenidate and amphetamine is not the same thing, and I have not experienced anything like what you've said.
I really don't think burn-out is as common as people say, high-doses are more like in the 100+mgs, and that's not in anything that is considered therapeutic and extended release.
Concerta wouldn't come in a 56mg tablet if it was expected to be neurotoxic.