Correct
No, absolutely not. The two are very different chemicals.
Amines are basic chemicals found in nature and in the lab, most chemicals are a form of an amine, I believe.
Aphetamine is a class is a class of drugs with certain neurochemical releasing properties. They can be found in cold medicine as decongestants (levo-methamphetamine is OTC, but does NOT get you high), medications for weight loss or ADD but the more famous amphetamines are quite well known for their euphoric properties.
Methylamphetamine is a stronger version of regular amphetamine that is found in Dexedrine or Adderall. The methyl position makes it more accessible to your brain, and as such becomes much more powerful and addictive.
Methylene-dioxy is a structural position that is attached long before the "methampetamine" gets onto the final molecule, so there is absolutely no meth involved in the manufacture of MDMA, completely different chemicals.
The MD position on MDMA causes the effects to change drastically, making the drug become MUCH more serotonergic, as well as causing higher release rates of the Love Hormone (oxytocin) and the hormone responsible for sexual pleasure (prolactin)
Methamphetamine however works primarily on dopamine, which is the brain's reward pathway. When you do something good in life, eat healthy food, go to the gym or get an A on a big test, it releases the natural hormones that make you feel good about accomplishing something and make you want to do it again. This is why meth is so addictive, it makes you think the drug is actually good for you and you want more and more and more of it... I know, I am an ex-amphetamine addict
MDMA is quite different though, if you try and use it as much as people use meth tolerance builds INSANELY fast and the side effects simply become too harsh to carry on. That's why a LOT of people ruin their life with meth and most people can use MDMA with little to no problems.. people simply practice moderation with ecstasy more often.
If you were to roll everyday taking more and more everyday as a meth head would do with shards though, yes it would likely do just as much, if not even more damage than meth. As long as you keep usage to less than one roll a month this is almost NEVER a problem for anyone, however. It's only when using too often that those kind of nasty effects show up.