1. Between the German study and the US study, the German comes out with a result that does NOT cater to what the funders wanted to find. I mean, I can't see how the German government could have WANTED to show ecstasy was apparently harmless (well, harmless in certain ways that were tested). So, all things being equal, I trust the German study more than the US study.
2. Just because lots of ecstasy users have mental/emotional problems or you used ecstasy and have mental/emotional problems, does NOT prove that ecstasy causes mental/emotional problems. The fact is, a lot of NON-ecstasy users have mental/emotional problems. It is possible an ecstasy user with mental/emotional problems would have had those problems anyway. Or perhaps the truth is somewhere in the middle, like a person might be on the verge of clinical depression, but perhaps would not go over the edge and would be fine BUT FOR the fact that the person takes ecstasy which exposes the person to unnaturally high highs and unnaturally low lows, that results in the person going over the edge and becoming clinically depressed. But, then again you could have many experiences that push you one way or the other if you are on the edge of some mental/emotional problem. A supportive lover, a bad break up, an insightful self-help book, a car accident, etc.
So, anyway, I think it is pretty sketchy for peole to say, "Hey, I know ecstasy causes mental problems because we know from the Dark Side that a lot of users have problems" or "I know it is bad for you because I used ecstasy and now I am manic depressive." These anecdotal experiences prove nothing without being quantified.
And, as I'm sure some one has noted before me, if you are TAKING ecstasy, you are a drug user and a lot of people take drugs (or take them to excess) BECAUSE they have mental/emotional problems, difficulty coping, etc. And so that even makes it dumber to assume that if some one takes drugs, and then has a mental or emotional problem, the drug caused it.
3. The German study only looked at certain aspects of brain functioning, and so it cannot be used as proof that Ecstasy causes no form of damage to the brain, or causes no mental/emotional problems. And, further, it certainly cannot be used to prove that Ecstasy use does not cause other damage, such as to the liver and kidneys and heart.
I'm looking forward to some study to reconcile the US and German studies (or debunk one or the other).
~psychoblast~