There is a relatively well-known study that shows the depletion of serotonin and destruction of serotonin-containing nerve fibers in the brains of monkeys after even short term use; here is the link: http://www.drugabuse.gov/Testimony/9-19-02Testimony.html .
I don't want to sound too negative, as the brain has amazing recuperative powers. But ecstasy is a very dangerous drug, and has even been associated with sudden death in new users for unclear reasons. Don't take it an 8th time.
well im not a doctor, but i was an Ecstasy addict for several years, so i know the ins and outs of how it works, what it can do to your body and the side effects. Ill tell you what i know...Everyone reacts to drugs slightly differently and there's a handful of side effects that can occur after using ecstasy, these side effects vary greatly..especially if your mdma(pure e) is laced or fake. Sometimes when you get a pill, the little symbol on it will be popping out, that's a surefire sign of fake e...made with pcp and other similar drugs...those can have completely different side effects. The more often that you take e, the harder it is for your body to recover; what ecstasy does is release a natural chemical that is in your brain, except instead of a normal amount, it releases a larger amount making everything wonderful; this is why depression is a typical side affect. However, body aches, extreme exhaustion, jaw pain(from clenching) and chemical imbalances causing things like stress, anxiety..extreme sadness without cause and even paranoia are all things that you might experience after taking e. It is not suggested to take this drugs more than a handful of times in your life, because every time you take it, the recovery may be that much more lengthily and severe. This is especially if your taking it often and close in time, like once or twice a week. Anyways, i would not suggest taking this drug, because you become emotionally dependent on it, the 'good feeling' is addictive and the recovery will keep getting worse; you will find yourself feeling all sorts of emotions that don't make sense or that are inappropriate. I know that it's a personal decision to stop and you probably won't until you're ready, but know that the consequences of this drug are all over the board because of the variety of other drugs laced with it and because of how the drug tampers with your brain chemistry.
Like i said, im not a doctor, but i do know a lot about this subject through a ton of research and personal experience.