I am a graduate student doing research in neuroscience, I will have a PhD in the next 12-18 months. I am also an Aspie, and I have the following to say:
Ecstasy IMO is the worst illegal drug in existence whether you are Autistic or NT. It permanently and irreversibly kills your brains serotonin cells. One interpretation of this is that, at a cellular and molecular level, ecstasy could make you more sad and less happy for the rest of your life! In addition you could be more prone to depression. I can not emphasize this strongly enough, if you are taking ecstasy do anything and everything in your power to stop taking it as soon as possible. I would not emphasize this as strongly with pot for example. But taking ecstasy, makes me cringe the same way I would if I was told some one had sprayed themselves with gasoline and decided to light a match. My response would be the same: you have irreversibly scarred your body. I can only hope that you get help ASAP to recover from your problems.
As for Autism, it is a brain developmental issue. In between the time that your parents conceived you and lets say 6 months after birth (although no one knows the exact time, and it is possible that it is different for different people), your brain takes a 'shape'. Although this is an oversimplification, the brain can take either a NT style developmental shape or an Autistic style developmental shape. These are developmental patterns based on how an embryo grows in the womb, and how the infant develops in the first 6-24 or so months of life.
By 6-24 or so months of life any human brain will be pretty much set to become either Autistic or NT. No one on earth even understands what the main differences between Autistic or NT brains, let alone has any idea how you can change one into another. Even if you could use a Star Trek like transporter to perform brain surgery on an Autistic reshaping one brain cell at a time (IMO this would be the only "cure" that I could imagine) the act of doing so would fundamentally change who you are so much that I would argue that it would be akin to a lobotomy.
With that said, some people hypothesize that if a mother is exposed to valproic acid (click for wikipedia link) while pregnant, the drug can increase the chances of her child being Autistic. There is evidence for other toxins increasing the chances of Autism as well in pregnant women. Drugs or toxins during pregnancy are the only possible way for a chemical to induce Autism.