HEALTH AND MEDICAL ISSUES :
WOMEN: PREGNANCY: HEALTH ISSUES :
MEDICAL: GENETICS :
ADOLESCENT: BEHAVIOR:
Combination of Genes and Prenatal Exposure to Smoking Increases
Teens' Risk of Disruptive Behavior
Date: Thu, 5 Mar 2009 12:32:38 -0500
From: "NIH OLIB (NIH/OD)" <olib@OD.NIH.GOV>
To: NIHPRESS@LIST.NIH.GOV
Subject: Combination of Genes and Prenatal Exposure to Smoking
Increases Teens' Risk of Disruptive Behavior
U.S. Department of Health and Human Services
NATIONAL INSTITUTES OF HEALTH NIH News
National Institute on Drug Abuse (NIDA)
<http://www.nida.nih.gov/>
Embargoed for Release: Wednesday, March 4, 2009, 12:00 a.m. EST
CONTACT:
Kim DiFonzo, NIDA
301-443-6245
e-mail:
media@nida.nih.gov
COMBINATION OF GENES AND PRENATAL EXPOSURE TO SMOKING INCREASES
TEENS' RISK OF DISRUPTIVE BEHAVIOR
NIDA Study Shows Different Gene Variants Influence this Risk for Girls and
Boys.
A study funded by the National Institute on Drug Abuse, a component of the
National Institutes of Health, shows that prenatal exposure to smoking
combined with a specific genetic variant places children at greatest risk
for behavioral problems. Many studies have established that there is an
increased risk of aggressive behavior in children exposed to cigarette
smoke before birth, a significant problem given that many women still
smoke during pregnancies. According to the National Survey on Drug Use and
Health, in 2006-2007 slightly more than 16 percent of pregnant women aged
15-44 (426,000) were current cigarette smokers.
A team of researchers led by the Institute for Juvenile Research,
University of Illinois at Chicago, identified a long-lasting influence on
behavior of the monoamine oxidase A (MAOA) gene variant following tobacco
exposure before birth. MAOA is an enzyme which regulates key
neurotransmitters*, or chemical messengers in the brain. Strikingly, the
genetic variant that confers this increased risk differs between boys and
girls.
"These findings illuminate how the interaction between genes and the
environment can mold behavioral patterns very early in development," said
NIDA Director Dr. Nora Volkow. "This research provides a foundation for
studies of the impact of these interactions on brain development during
pregnancy."
The researchers studied 176 non-Hispanic white youth, whose average age
was 15, and their biologic mothers. In contrast with previous studies of
prenatal smoking that have measured exposure based on the mother's
recollection of past smoking, this study obtained accurate measurements of
smoking behaviors during the actual pregnancy.
In boys, with the low-activity MAOA (MAOA-L) gene variant, exposure to
prenatal smoking was associated with increased disruptive social
interactions, including aggressive behaviors and serious rule-violating.
"Low activity" means that the gene produces less of its product, the
enzyme monamine oxidase A. In contrast, exposure to prenatal smoking was
associated with increased disruptive behavior in girls who had the
high-activity MAOA (MAOA-H) variant. For both boys and girls, the more
their mothers had smoked during pregnancy, the higher the risk of
disruptive behavior.
Additionally, on computerized tasks, girls with both the MAOA-H variant
and prenatal exposure to smoking had a greater tendency to perceive anger
in a range of facial expressions, a tendency that researchers term
"hostile attribution bias." This effect was not seen among boys.
"The tendency to over-perceive anger suggests the possibility that the
combination of prenatal tobacco exposure and the MAOA risk variant affects
the brain's processing of emotional cues," said the study's principal
investigator, Dr. Lauren S. Wakschlag, associate professor of psychiatry
at the Institute for Juvenile Research, University of Illinois at Chicago.
"Individuals with a greater tendency to perceive hostility in others are
more likely to respond aggressively. These findings provide us with clues
to the possible mechanism by which prenatal exposure may exert its effects
on brain and behavior. Clearly, close attention to sex differences in
these patterns will be critical for future studies."
Dr. Wakschlag led the study in collaboration with colleagues from the
Institute for Juvenile Research as well as researchers from the National
Institute of Mental Health (which is also a component of the National
Institutes of Health); the University of Chicago; Harvard University
Medical School; and the University of York, England.
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---------------------------------
* i.e., dopamine, epinephrine, norepinephrine, serotonin
##
This NIH News Release is available online at:
<http://www.nih.gov/news/health/mar2009/nida-04.htm>
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