Smart drugs
Does getting old have to mean worsening memory, slower reactions and
fuzzy thinking?
AROUND the age of 40, honest folks may already admit to noticing
changes in their mental abilities. This is the beginning of a gradual
decline that in all too many of us will culminate in full-blown
dementia. If it were possible somehow to reverse it, slow it or mask
it, wouldn't you?
A few drugs that might do the job, known as "cognitive enhancement",
are already on the market, and a few dozen others are on the way.
Perhaps the best-known is modafinil. Licensed to treat narcolepsy, the
condition that causes people to suddenly fall asleep, it has notable
effects in healthy people too. Modafinil can keep a person awake and
alert for 90 hours straight, with none of the jitteriness and bad
concentration that amphetamines or even coffee seem to produce.
In fact, with the help of modafinil, sleep-deprived people can perform
even better than their well-rested, unmedicated selves. The forfeited
rest doesn't even need to be made good. Military research is finding
that people can stay awake for 40 hours, sleep the normal 8 hours, and
then pull a few more all-nighters with no ill effects. It's an open
secret that many, perhaps most, prescriptions for modafinil are
written not for people who suffer from narcolepsy, but for those who
simply want to stay awake. Similarly, many people are using Ritalin
not because they suffer from attention deficit or any other disorder,
but because they want superior concentration during exams or
heavy-duty negotiations.
The pharmaceutical pipeline is clogged with promising compounds -
drugs that act on the nicotinic receptors that smokers have long
exploited, drugs that work on the cannabinoid system to block
pot-smoking-type effects. Some drugs have also been specially designed
to augment memory. Many of these look genuinely plausible: they seem
to work, and without any major side effects.
So why aren't we all on cognitive enhancers already? "We need to be
careful what we wish for," says Daniele Piomelli at the University of
California at Irvine. He is studying the body's cannabinoid system
with a view to making memories less emotionally charged in people
suffering from post-traumatic stress disorder. Tinkering with memory
may have unwanted effects, he warns. "Ultimately we may end up
remembering things we don't want to."
Gary Lynch, also at UC Irvine, voices a similar concern. He is the
inventor of ampakines, a class of drugs that changes the rules about
how a memory is encoded and how strong a memory trace is - the essence
of learning (see New Scientist, 14 May, p 6). But maybe the rules have
already been optimised by evolution, he suggests. What looks to be an
improvement could have hidden downsides.
Still, the opportunity may be too tempting to pass up. The drug acts
only in the brain, claims Lynch. It has a short half-life of hours.
Ampakines have been shown to restore function to severely
sleep-deprived monkeys that would otherwise perform poorly.
Preliminary studies in humans are just as exciting. You could make an
elderly person perform like a much younger person, he says. And who
doesn't wish for that?
from
New Scientist |
