Reduced Frontal-Lobe Activity and Impulsivity May Be Linked to Alcoholism Risk
Jan 8, 2007
A new study of brain processes provides support for the theory that increased impulsivity,
or a lack of impulse control, is involved in a predisposition to developing many psychiatric
disorders, including alcohol dependence. Results of the study – conducted by researchers
at SUNY Downstate Health Sciences University in Brooklyn – are published in the January
issue of Alcoholism: Clinical & Experimental Research (ACER).
“Altered impulsivity is a prominent manifestation in many disinhibitory psychiatric
disorders, such as alcohol- or substance-related disorders, conduct disorder, attention-deficit
hyperactive disorder (ADHD), antisocial personality disorder (ASP), bipolar disorder,
impulse control disorders, and so on,” said Bernice Porjesz, Professor of Psychiatry
& Behavioral Sciences, and Director of the Henri Begleiter Neurodynamics Laboratory
at SUNY Downstate Health Sciences University.
“Individuals suffering with these disorders may frequently and unpredictably act without
planning in advance or without regard to the negative consequences of their behaviors,
which in turn can result in serious aftermath. In severe cases, it may lead to danger
to the patient or to others.”
Porjesz added that the majority of psychiatric diseases are “complex diseases,” meaning
that their development is influenced by an underlying biological susceptibility of
genetic factors, environmental factors, and interactions among multiple genes and
the environment.
“Disinhibitory disorders share many similar clinical presentations as well as similar
neurobiological abnormalities such as brain waves,” said Porjesz. “This suggests
that this group of disorders may have some underlying genetic vulnerabilities in common
that contribute to the disorders. One recent study of genetic and environmental contributions
to internalizing and externalizing disorders determined that the single most important
factor underlying externalizing disorders is a genetic liability involving impulse
control.”
Results of the study showed that alcohol-dependent subjects, as well as those individuals
with high impulsivity, had significantly lower P3 amplitudes (an evoked response of
the brain reflecting the level of neural inhibition in the central nervous system
- the larger the P3, the more the inhibition) and reduced frontal-lobe activity while
processing visual target signals.
“This is the first study to demonstrate that reduced brain activity in the frontal
lobe during processing of target visual stimuli is highly related to impulsivity,
regardless of a clinical diagnosis such as alcoholism,” said Porjesz. “Genetically
influenced underlying factors, such as neural disinhibition and impulsivity, involve
frontal-lobe function and influence a wide range of clinical outcomes. Thus, the
low P3 amplitude and reduced frontal activation that we found reflect risk for the
development of many externalizing disorders, not just specifically alcohol dependence.”
As part of a large nine-center collaborative study known as COGA (Collaborative Study
on the Genetics of Alcoholism), Dr. Porjesz and colleagues are also trying to identify
genes associated with impulsivity, and the underlying predisposition involved in disinhibitory
disorders, by following young offspring of alcoholics with “risk genes” as they go
though the age of risk and respond to their environmental factors.
#
Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International
Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, “Reduced
Frontal Lobe Activity in Subjects with High Impulsivity and Alcoholism,” were: Andrew
C. H. Chen, Madhavi Rangaswamy, Chella Kamarajan, Yongqiang Tang, Kevin A. Jones,
David B. Chorlian, Arthur T. Stimus, and Henri Begleiter of the Neurodynamics Laboratory
in the Department of Psychiatry at SUNY Downstate Health Sciences University in Brooklyn.
The study was funded by the National Institute on Alcohol Abuse and Alcoholism.
Journalists: A full copy of the manuscript may be obtained by contacting Mary Newcomb
at the ACER Editorial Office: 317.375.0819 or mnewcomb-acer@earthlink.net . The project is supported by the Addiction Technology Transfer Center Network.
### About SUNY Downstate Health Sciences University Downstate Health Sciences University in Brooklyn is one of four academic health centers
(AMCs) in The State University of New York (SUNY) 64-campus system and the only SUNY
AMC in New York City dedicated to health education, research, and patient care for
the borough’s 2.7 million residents. Its flagship hospital, University Hospital at
Downstate (UHD), is a teaching hospital and benefits from the expertise of Downstate’s
exceptional medical school and world-class academic center research facilities. With
a staff of over 800 physicians representing 53 specialties and subspecialties, Downstate
offers comprehensive healthcare services to the community. UHD provides high-risk neonatal and infant services, pediatric nephrology, and dialysis
for kidney diseases and is the only kidney transplantation program in Brooklyn. Beyond
its clinical expertise, Downstate houses a range of esteemed educational institutions,
including its College of Medicine, College of Nursing, School of Health Professions,
School of Graduate Studies, and School of Public Health. Downstate fosters innovation
through its multifaceted biotechnology initiative, the Biotechnology Incubator and
BioBAT, which support early-stage and more mature biotech companies.