E IS FOR EVIDENCE

Basing Drugs Policy On Flawed Science Helps No One

THERE are no ironclad certainties in science. All theories and observations
have their critics. And just because a finding appears in a peer-reviewed
journal doesn't make it the last word: journals exist as much to enliven
debate as to get it right. So on one level, our inquiry into the quality of
the scientific evidence suggesting ecstasy harms brain cells is perhaps
unsurprising (see p 26).

What we found is that certain high-profile studies claiming ecstasy causes
lasting damage are based on flawed brain scans. But so what? Other teams
will eventually repeat the experiments with better techniques. The truth
will out. And in the meantime, does it matter if the evidence is shaky as
long as it sends a suitably grim warning to people taking the drug?

In this case it matters a lot. These scans are not minor bits of academic
science. They can be selectively presented to make it look as though
ecstasy users have blotchy holes in their brains (see left). It's a potent
visual message that's been seized on by drugs education campaigns and
continues to guide those who set drugs penalties. That might just be
defensible if the findings were simply disputed or uncertain. But our
investigation suggests the experiments are so irretrievably flawed that the
scientific community risks haemorrhaging credibility if it continues to let
them inform public policy.

Parents, teachers and teenagers are increasingly clamouring for reliable
evidence on the harm drugs do, not moralising or hyped pseudo-science. And
once created, myths about illicit drugs are hard to slay. In the 1970s,
scientists published papers purporting to show that cannabis damages brain
cells in monkeys. The experiments were refuted, but anti-drugs campaigners
made sure the earlier message stuck. Even today, some drugs education
programmes in the US wrongly claim that science has proved marijuana can
destroy brain cells.

We are not saying that ecstasy is harmless to brain cells. It might not be.
But the jury is still out. Which means scientists must resist the
temptation to turn their always complex-and sometimes flawed-findings into
simple scare stories in pursuit of grants and headlines. The scientific
community must also do more to persuade people that it really is impartial
and not following a political agenda. Scores of published papers examine
the neurotoxic potential of ecstasy. Very few do the same for Prozac-style
antidepressants, even though these drugs act on the same serotonin synapses
in the brain as ecstasy and are swallowed daily by millions. Where are the
colourful scans proving that these legal substances don't cause lasting
biochemical changes?

When it comes to illicit drugs, too many critics already accuse scientists
of being in the pocket of government paymasters eager for scary evidence of
harm. Scientists must not hand them ammunition on a plate. They must rise
above the politics of the drugs war by ensuring the same high level of
scrutiny for prescription pills-and by clearing up the mess about brain scans.