Focusing on the Roots of Nicotine Addiction: The Genetic Aspects of Cigarette Smoking
As has been pointed out numerous times, there are
some individuals who use alcohol, tobacco or other drugs of abuse
and become substance abusers-continuing to drink, smoke or inject
themselves with a drug(s) of abuse even though doing so causes
them serious problems. Others are able to limit or avoid use of
these harmful substances well before they become abusers or addicts.
To clarify the role that genes play in predetermining those individuals
who are more vulnerable to a substance of abuse, twin studies
are a first step in exploring genetic and environmental factors
which result in the development of dependence and addiction. If
genes significantly influence the risk for abuse, identical (monozygotic)
twins who share the same genes will tend to be alike (concordant)
in their response to a particular agent of abuse. On the other
hand, fraternal twin pairs who only have 50 percent of their genes
in common will be less concordant. By comparing the degree of
concordance in monozygotic as compared to dizygotic twin pairs,
scientists can estimate the extent to which genes influence vulnerability
to a specific drug of abuse.
Methoxsalen Decreases Desire to Smoke
In 1998, NIDA- supported research found a genetic variation that
makes some people less likely to become addicted to nicotine than
others. They also found that people with this gene who were addicted
were likely to smoke fewer cigarettes and have an easier time
quitting smoking. The researchers found a medication called Methoxsalen
that mimics the effects of the above-mentioned genetic variation.
Currently used in treatment for severe psoriasis, Methoxsalen
works for smokers by "...partially blocking the body's ability
to break down nicotine, significantly improving the effectiveness
of oral nicotine replacement in reducing a smoker's urge for nicotine."