E Is For Evidence
New Scientist (UK)
April 20, 2002
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.