Question:
The researchers studied 519 volunteers including current or past Ecstasy users, cannabis smokers and people who had never taken drugs."So, presumeably no evidence was found to suggest that cannabis causes brain damage? which found no long term brain damage from ecstasy, didn't receive quite as much (ie none) media attention.

BTW, what exactly are 'depression levels'? Do they measure them with a dipstick or is it more technical than that? Do these people have depression meters on their foreheads?

Without sounding like some old 60's hippy, taking ecstasy was an eye opener for me and most other people I know who have taken it. It gives you a little perspective shift (more than any other drug I've tried, including LSD). So I'm sure if you gave people who have taken ecstasy a standard psyke test they will probably come across as a little less satisfied with the standard vision of life than your 'regular Joe Sixpack'."They found those who had tried Ecstasy on only a few occasions had depression levels four times higher than those who had taken a range of other drugs."- equal, "they were a bit less happy with the standard status quo of life as passed down by the government 'how to be an average citizen' department'?

Answer: Brain signals are rather complex, a combination of electric and chemical impulses. The synapses are critical to the brain's functioning, AFAIK; various chemicals such as L-dopamine and d-lysergic acid diethylamide, more commonly known as LSD (a very dangerous psychoactive drug), and phencyclidine, more commonly known as PCP (an even more dangerous psychoactive drug) vary the functioning of these synapses. Some drugs damage them irreparably -- "ecstasy", more properly known as 3-4-methylenedioxymethamphetamine or MDMA, can irreparably damage the brain, presumably by ruining the chemicals in the synapses or serotonin inhibitors or generators, and leave the abuser unable to even move.