Maternal smoking tied to
inhibition-related brain differences in kids
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[May 15, 2014]
By Andrew M. Seaman
NEW YORK (Reuters Health)
— Smoking while pregnant may be
linked to less control over inhibitions when the child is an adult, a
new study that looked at brain scans suggests.
People whose mothers smoked during pregnancy had
weaker responses in the regions of their brains known to be involved
in inhibition control, compared to those whose mothers didn’t smoke,
Inhibition control relates to how people keep their impulses in
check and resist distractions in certain situations.
“What’s quite surprising is to find such a reliable effect of
prenatal smoke exposure that occurred 25 years before,” Nathalie
Holz is the study’s lead author from Mannheim/Heidelberg University
She and her colleagues write in JAMA Psychiatry that about 22
percent of European women smoke and about half of them continue to
smoke during pregnancy.
Smoking while pregnant has been tied to
attention-deficit/hyperactivity disorder, or ADHD, among kids.
Children with the condition usually have trouble concentrating and
controlling their impulses.
“Now we were interested in what the specific mechanisms are behind
this association,” Holz said.
For the new study, she and her colleagues used data collected from
178 mothers and their 25-year-old children, who had been tracked
The researchers used special magnetic resonance imaging (MRI) scans
to see what activity was going on in the young adults’ brains when
they were given a test to measure their control over inhibitions.
They found that the brains of the 38 young adults with mothers who
smoked during pregnancy didn’t show as much of a response in the
areas that are important to inhibition control as those of the 140
people with non-smoking mothers.
The results remained the same when the researchers accounted for
other factors, such as parents’ smoking habits after birth and
children’s sex, psychological problems and substance abuse.
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What’s more, the young adults whose mothers smoked during pregnancy
exhibited more ADHD symptoms between ages two and 15, compared to
those whose mothers didn’t smoke.
Although the authors can’t explain what caused the differences in
brain responses, Holz said they could be related to how those parts
of the brain react to nicotine. More studies are needed to figure
that out, she said.
“This clearly shows that pregnant women smoking is associated not
with just ADHD behavior but other impulsivity behavior,” Pradeep
Bhide told Reuters Health.
Bhide, who studies brain development at the Florida State University
College of Medicine in Tallahassee, was not involved with the new
“I think this confirms previous results in other human studies and
some of the other studies in animals and rodents,” he said.
Bhide said his own research has shown the effect of maternal smoking
may last into the second generation - meaning a woman’s grandchild
may also be at an increased risk of developing ADHD if she smokes
JAMA Psychiatry, online May 14, 2014.
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