Recovery of dopamine function emerges
with recovery from smoking
By Dr.Fourkan Ali
:
A new study reports
that smoking-related deficits in brain dopamine, a chemical implicated in
reward and addiction, return to normal three months after quitting. The normalization
of dopamine systems suggests smoking-related deficits are a consequence of
chronic smoking, rather than a risk factor. These findings raise the
possibility that treatments might be developed that normalize the dopamine
system in smokers.
A new study in Biological
Psychiatry reports that
smoking-related deficits in brain dopamine, a chemical implicated in reward and
addiction, return to normal three months after quitting. The normalization of
dopamine systems suggests smoking-related deficits are a consequence of chronic
smoking, rather than a risk factor. These findings raise the possibility that
treatments might be developed that normalize the dopamine system in smokers.
According to first
author Dr. Lena Rademacher, postdoctoral fellow at the University of Lübeck in
Germany, a major challenge in understanding substance-related disorders lies in
uncovering why only some individuals become addicted.
Researchers think some
people could possess a trait that predisposes them to addiction, and suspect
that brain circuits involving dopamine may be involved. Drugs of abuse release
dopamine, and addiction to nicotine is associated with abnormalities in the
dopamine system. But researchers are uncertain if smoking induces those
abnormalities or if they already exist and contribute to risk of nicotine
addiction.
Senior author Dr. Ingo
Vernaleken, Professor at RWTH Aachen University in Germany, led a team of
researchers examining dopamine function in chronic smokers before and after
long-term cessation. The researchers used a brain imaging technique called
positron emission tomography to measure an index of the capacity for dopamine
production in 30 men who were nicotine-dependent smokers and 15 nonsmokers.
After performing an initial scan on all participants, 15 smokers who
successfully quit were scanned again after three months of abstinence from
smoking and nicotine replacement.
The initial scan
revealed a 15-20% reduction in the capacity for dopamine production in smokers
compared with nonsmokers. The researchers expected this impairment to persist
even after quitting, which would suggest it could be a marker of vulnerability
for nicotine addiction. "Surprisingly, the alterations in dopamine
synthesis capacity normalized through abstinence," said Rademacher.
The role of dopamine
in vulnerability toward nicotine addiction cannot be excluded, but the findings
suggest that altered dopamine function of smokers is a consequence of nicotine
consumption rather than the cause.
Dr. John Krystal,
Editor of Biological Psychiatry, noted the implications of these findings for developing better
ways to help smokers trying to quit. "This study suggests that the first
three months after one stops smoking may be a particularly vulnerable time for
relapse, in part, because of persisting dopamine deficits. This observation
raises the possibility that one might target these deficits with new
treatments."
Story
Source:
The above post is
reprinted from materials provided by Elsevier. Note: Content may be edited for style
and length.
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