Scientific American Mind-June/July 2007

(head lines)
A Drug for Down Syndrome
Scientists may have fi nally found a drug candidate
for reducing the mental retardation
caused by Down syndrome. After as little as
two weeks on the drug, mice with a genetic impairment
similar to the syndrome performed as
well as normal animals did on learning tests.
The learning and memory problems
characteristic of Down syndrome may occur
because its sufferers’ brain cells are unable to
form new synaptic connections with
neighboring neurons. This inhibition could be
the result of overactive GABAA receptors—tiny
ion channels on neurons. The drug the
researchers tested, pentylenetetrazole (PTZ),
interferes with the GABAA receptors, allowing
new synapses to be formed at a normal rate.
For two to four weeks, researchers gave
low doses of PTZ to mice bred to have an extra
copy of one of their chromosomes. As in Down
syndrome, this genetic anomaly causes
malformed facial bones and learning
problems. Immediately after treatment with
PTZ, the animals’ scores on two memory
tests—for recognizing objects they had seen
before or remembering how they last entered a
maze—were on par with normal mice. Two
Mothers’ Little Criminals
In late February, Rosie Costello, a mother from Vancouver,
Wash., pleaded guilty to Social Security fraud and conspiring
to defraud the government. Her crime? For 20 years,
Costello had been forcing her two healthy children to fake
mental retardation to collect disability benefi ts.
Parents such as Costello, who criminally exploit their
children for money, may be responsible for more juvenile
months later the altered mice still did much
better than they would have done otherwise.
The treatment “is allowing the normal
properties of neurons to work,” says Stanford
University neurobiologist Craig Garner, whose
group performed the experiments. “This
slowly, over time, leads to an improved circuit.”
Although the study results are hugely
promising, there is a catch: PTZ, formerly used
to treat psychiatric disorders, was taken off
the market 25 years ago after being found to
be ineffective and to cause dangerous
seizures in some people. The dose used in the
current study was much smaller than the dose
that provoked seizures, however, so the
researchers believe there is a good possibility
that the drug can be used safely. —JR Minkel
A new drug
may allow
children
with Down
syndrome to
learn at the
rate of their
healthy peers.
lawbreaking than our society currently recognizes, according
to experts such as forensic psychologist Kathryn Seifert of
Eastern Shore Psychological Services in Maryland, who has
been studying youth delinquency for 30 years.
“Children don’t just wake up one day and say ‘I want to
be a thief when I grow up,’ ” Seifert says. “It is, at least in
part, learned behavior.” Of the delinquent youths Seifert
works with in her clinic, 62 percent have parents who are
either antisocial, mentally ill or substance abusers.
Some of these kids could
simply be imitating their parents’
behavior, says David Brandt, a
psychologist at the City University
of New York. Seifert, however,
maintains that some parents do
purposely teach their kids criminal
behavior—such as shoplifting or
prostitution—for their own fi nancial
gain. “I’ve certainly had a number
of them in my practice,” she says.
According to Seifert, the fi rst
steps in stopping such abuse are
raising awareness about it and
identifying exploited children early
on. If these kids can be helped
when they are still young, they can
be prevented from developing longterm
problems that could lead
them to abuse their own children in
the same way, she notes.
—Melinda Wenner
12 SCIENTIFIC AMERICAN MIND June/July 2007
COPYRIGHT 2007 SCIENTIFIC AMERICAN, INC.
LAUREN SHEAR Photo Researchers, Inc. (top); CORBIS (bottom)