Smoking,
Drinking Work Together to Harm Brain
1/25/2006
Join
Together
Both separately
and in concert, smoking and drinking cause harm to the brain --
bad news for the majority of alcoholics who also smoke.
A recent symposium
sponsored by the Research Society on Alcoholism addressed the impact
of smoking and alcoholism on brain neurobiology and function. "Recent
neuroimaging studies of chronic smokers have shown brain structural
and blood-flow abnormalities," said Dieter J. Meyerhoff, professor
of radiology at the University of California at San Francisco and
an associate researcher at the Veterans' Affairs Medical Center
in San Francisco. "Specific cognitive dysfunction among active
chronic smokers has been reported for auditory-verbal learning and
memory, prospective memory, working memory, executive functions,
visual search speeds, psychomotor speed and cognitive flexibility,
general intellectual abilities, and balance. We also believe that
the adverse effects of smoking, just like drinking, likely take
many years to impact brain function significantly, and interact
with age to produce a level of dysfunction that is apparent on cognitive
tests."
"These
effects are similar to effects that in the past have been attributed
solely to the excessive consumption of alcohol," he added.
"As chronic alcohol drinking and chronic smoking more often
than not co-occur, researchers have begun to realize that the brain
effects previously attributed to alcohol drinking alone may in fact
be the result of both drinking and smoking. This realization may
have consequences for how we look at treatment for alcohol-use disorders."
Participants
at the June 2005 symposium said that genetics as well as the pharmacological
interplay between alcohol and nicotine may play a role in the fact
that so many heavy drinkers are also heavy smokers.
"Any behavioral
manifestation, including alcoholism or addiction to nicotine, is
a result of genetic-environment interactions," said researcher
Yousef Tizabi. "Drugs, including alcohol and nicotine, may
affect different individuals differently, depending on their genetic
make-up. Similarly, drug-drug interactions are also influenced by
genetic factors. Therefore, co-morbidity of drinking and smoking
can be considered to be a final outcome of genetics, environment,
and pharmacological interactions between alcohol and nicotine."
Researchers
said that smoking may affect a key amino acid (GABA) in the brain,
meaning that drug therapy for alcohol withdrawal may have different
effects on smokers than nonsmokers. Scientists also reported that
MRI studies have shown that smoking makes alcohol-induced brain-tissue
loss and neuronal injury worse among alcoholics who have recently
detoxed. "Our analyses showed that chronically smoking alcoholics
have greater brain abnormalities -- that is, less brain tissue measured
by structural MRI, and more neuronal injury measured by MRSI --
at the beginning of their treatment for alcoholism than nonsmoking
alcoholics." said Meyerhoff. "And both groups had more
brain abnormalities than nonsmoking light drinkers."
The symposium
results were published in the February 2006 issue of the journal
Alcoholism: Clinical & Experimental Research.
|