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 Medical Center 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 Medical Center.
“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.
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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 Medical Center 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 Medical Center SUNY Downstate Medical Center, founded in 1860, was the first medical school in the
United States to bring teaching out of the lecture hall and to the patient’s bedside.
A center of innovation and excellence in research and clinical service delivery, SUNY
Downstate Medical Center comprises a College of Medicine, College of Nursing, School
of Health Professions, a School of Graduate Studies, School of Public Health, University
Hospital of Brooklyn, and a multifaceted biotechnology initiative including the Downstate
Biotechnology Incubator and BioBAT for early-stage and more mature companies, respectively.
SUNY Downstate ranks twelfth nationally in the number of alumni who are on the faculty
of American medical schools. More physicians practicing in New York City have graduated
from SUNY Downstate than from any other medical school.