I'll admit I don't know much about this, but Sam Harris says that while he had good experiences with MDMA in the past, he warns people against it now because the evidence is clear that it's a neurotoxin.
You will find serious scientific evidence on both sides arguing for and against, but since three beers floors me the next day and completely destroys my ability to think clearly, where MDMA refreshes and revitalizes pretty much every mental and sensory organ, I'll just go with my own findings on the matter :)
This is the article I always like to post whenever the discussion comes up:
"Pure MDMA can be 'safe' for adults", says BC's top health official http://www.cbc.ca/news/canada/british-columbia/pure-ecstasy-...
...And this video from 60 Minutes ("Ecstasy Rising") pretty much describing the demonization of MDMA as an elaborate government frame-up: https://www.youtube.com/watch?v=DNpFqJcJcps&feature=kp
The fact that you enjoy taking it doesn't mean that it is not a neurotoxin, just as the fact that I enjoy a martini doesn't mean that alcohol is not carcinogenic.
Again, not my area of expertise, but I think it's notable that a neuroscientist with a rational attitude toward drugs who recounts his own positive experiences with MDMA says that he wouldn't take it now specifically because of what he claims is conclusive evidence that it kills nerve cells.
IIRC there are others that have been found to have similar action but without the neurotoxicity. MBDB was one I think.
Personally I'd love to try EVE and EDEN too... but that's a pipedream in a world where it's rare you can ever know what you're getting.
The ones that have similar action (though subjectively don't really come that close) are the aminoindane-class analogues. They're interesting in their own right, too.
MDAI is odd and not all that much fun (on its own at any rate), and AFAICT from reading various forums, 2-AI and NM-2-AI don't really seem to do much for people either.
The neurotoxicity has been demonstrated in rats, but at a dose that would be fatal in humans. Rats have better tolerance of the effect that mdma has on thermo-regulation and this allows the neurotoxic effect to manifest.
If you gave a dose to a human that was sufficient to kill nerve cells, you would kill the human.
Like I said, no citation to hand (someone else maybe??), but this is food for thought I think.
I suspect that MDMA and related are somewhat physically harmful but is it more neurotoxic and has a greater addictive potential than legal drugs like alcohol? I don't think so.
I am a neuroscientist (in training, at least, in a subdiscipline that's only somewhat related but does occasionally involve drugging monkeys). There is good evidence that frequent use and probably even rare use of MDMA is bad for brains. Neurons don't necessarily die, but axons disappear. It is not clear that rare use of MDMA can cause lasting cognitive impairment in humans.
While DrugMonkey is sometimes a bit of an asshole, I don't find much fault with his assessment of the current state of MDMA research in this post: http://scientopia.org/blogs/drugmonkey/2012/07/25/single-ora.... Note the caveat in the comments: although MDMA is probably neurotoxic, it is still not clear that the neurotoxicity translates to behaviorally meaningful deficits. There exist studies that have shown such deficits, but there also exist studies that have not. Most studies are correlational; I have yet to see a longitudinal study that provides convincing evidence that MDMA itself is a causative factor.
"The "permanent brain damage" is based totally on studies done with
experimental animals, with the findings extrapolated to encompass the
human subject. In a simple statement, there have been no studies in man
that have indicated brain damage.
The "holes in the brain" is an even more outrageous deception. These
popular holes are areas in brain scans that appear less active in
attracting radiolabelled agents that are agonists for certain receptor
site areas. The pictures that are shown for comparison are not of the
same person with or without MDMA in them, but of different people, one
of whom has used a lot of ecstasy and the other one without any such
history. The quintessence of this line of mythology is an article that
appeared recently in the Willamette Week. It not only assured the
reader that there were holes generated by serotonin loss, but that they
became flooded with dopamine (the default neurotransmitter) and, being
attacked by hydrogen peroxide, produced rust.
Sorry, drug warriors. No damage, no holes, no rust."[1]
I would personally be far less concerned about the neurological/mental effect of ecstasy itself than the purity and identify of whatever passes for ecstasy.
This is a very unfortunate effect of the drug war: it makes everyone less safe.
If drugs were legalized, they could be regulated and their purity and dosage could be reliably labeled, just as currently legal drugs are in your neighborhood pharmacy, and people dying because of counterfeit drugs would mostly be a thing of the past.
[1] - http://www.cognitiveliberty.org/shulgin/adsarchive/brainhole...
[2] - https://www.erowid.org/chemicals/mdma/mdma_neurotoxicity.sht...