SO HOW DANGEROUS IS ECSTASY?

While it remains true that there are concerns over long-term risks,
and that an unlucky few will always die as a result of taking the
drug, clubbers planning to take ecstasy at the weekend now have one
less thing to worry about.

This week scientists were forced to admit that an alarming study
suggesting that a single tablet could cause irreversible brain damage
(and trigger the onset of Parkinson's disease) was nonsense. The
results of the experiments provoked dire warnings of the dangers of
the drug last year, but it has now emerged that a labelling error
meant the scientists were not testing ecstasy, but a different
substance entirely - one that was already known to cause brain damage.

The blunder will be officially announced tomorrow, when the
prestigious American journal Science, which published the original
results, prints a retraction that will effectively wipe the dodgy
findings from the scientific record.

"Scientists around the world do get it wrong, but this is fairly
major, major getting it wrong," says Valerie Curran of University
College London, who also researches the possible dangers of taking
ecstasy. She says the discredited findings caused such a stir because
they seemed to show ecstasy affecting the brain in a totally new way.
The experiments indicated that ecstasy damaged the cells responsible
for producing the brain chemical dopamine, whereas other scientists
had only ever seen an effect on cells that produce a different
chemical called serotonin. Reduced dopamine levels are associated with
Parkinson's disease.

More dramatically, two of the 10 monkeys and baboons given injections
of what the researchers thought was ecstasy quickly died.

The retraction does not give ecstasy a clean bill of health. The drug
can easily kill as this week's Manchester court case over the death of
10-year-old Jade Slack, who died after swallowing five ecstasy
tablets, acutely demonstrates. (Although clubbers are quick to point
out that the death rate among those taking the drug each weekend is
lower than in activities such as downhill skiing.)

There are also concerns over the long-term consequences of the drug's
possible effects on brain serotonin levels, which will become the
focus again now the dopamine effect has been exposed as a red herring.
"Serotonin mediates lots of different behaviours, so if you have an
extreme depletion of serotonin then you will see a variety of
personality problems," says Michael Morgan, an experimental
psychologist at Sussex University. Much of the work remains
controversial, but Morgan says most people in the field agree that a
link between ecstasy and reduced serotonin levels has been
conclusively demonstrated in animal studies.

Research with humans is more difficult, as it is hard to measure
levels of serotonin accurately in living tissue. Morgan has tested the
memory and other brain functions of self-confessed ecstasy users and
says there is a link, particularly among those people who have taken
more than 100 tablets over the years. "Most of my work is suggesting
that there are selective cognitive deficits associated with ecstasy
use and that this appears to be connected to the idea of serotonin
depletion," he says.