Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.

Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.


Genetics may shape addiction

13 September 2012, 09:48

Have you ever wondered why some people find it so much easier to stop smoking than others? New research shows that vulnerability to smoking addiction is shaped by our genes.

A study from the Montreal Neurological Institute and Hospital - The Neuro, McGill University shows that people with genetically fast nicotine metabolism have a significantly greater brain response to smoking cues than those with slow nicotine metabolism.

 Previous research shows that greater reactivity to smoking cues predicts decreased success at smoking cessation and that environmental cues promote increased nicotine intake in animals and humans. This new finding that nicotine metabolism rates affect the brain's response to smoking may lead the way for tailoring smoking cessation programs based on individual genetics.

Brain activation to cues

Scans show areas of brain activation in response to smoking cues in people with fast nicotine metabolism (upper row) and slow nicotine metabolism (bottom row). Brain regions are more activated in individuals with fast nicotine metabolism.

Smoking cues, such as the sight of cigarettes or smokers, affect smoking behaviour and are linked to relapse and cigarette use. Nicotine metabolism, by a liver enzyme, also influences smoking behaviour. Variations in the gene that codes for this enzyme determine slow or fast rates of metabolism and therefore, the level of nicotine in the blood that reaches the brain. In the study smokers were screened for their nicotine metabolism rates and their enzyme genotype.

 Participants were aged 18 – 35 and smoked 5-25 cigarettes daily for a minimum of two years. People with the slowest and fastest metabolism had their brain response to visual smoking cues measured using functional MRI. Fast metabolisers had significantly greater response to visual cigarette cues than slow metabolisers in brain areas linked to memory, motivation and reward, namely the amygdala, hippocampus, striatum, insula, and cingulate cortex.

Findings of brain’s response to smoking

"The finding that nicotine metabolism rate has an impact on the brain's response to smoking cues supports our hypothesis that individuals with fast nicotine metabolism rates would have a greater brain response to smoking cues because of close coupling in everyday life between exposure to cigarettes and surges in blood nicotine concentration. In other words they learn to associate cigarette smoking with the nicotine surge," says clinician-scientist Dr Alain Dagher, lead investigator at The Neuro.

"In contrast, individuals with slow metabolism rates, who have relatively constant nicotine blood levels throughout the day, are less likely to develop conditioned responses to cues. For them, smoking is not associated with brief nicotine surges, so they are smoking for other reasons. Possibilities include maintenance of constant brain nicotine levels for cognitive enhancement (ie, improved attention, memory), or relief of stress or anxiety."

Future research could focus on improving smoking cessation methods by tailoring treatments for different types of smokers. One possibility is to measure the rate of nicotine metabolism as part of the therapeutic decision-making process. For example, targeting cue-induced relapse risk may not help those with slow nicotine metabolism, who are more likely to benefit from long-acting cholinergic drugs such as the nicotine patch, consistent with previous clinical trials.

Conversely the use of non-nicotine based therapies aimed at reducing craving may help fast metabolisers, as demonstrated for buproprion, an anti-depressant that has been used for smoking cessation.

- EurekAlert

Tags smoking

Read News24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Read more from our Users

Nigeria @ 56: Words to my green f...

A leader’s job is not to dictate, but rather to be respected, admired and be a trustee, of the land we love, with so much potential, a land which should be freer than free. Its still a long way to fufilling our destiny! Read more...

Submitted by
Isaac Asabor263
Recession: An opportunity for Nig...

The recession should be seen as an opportunity for the country’s promotion as long as we all collectively conduct ourselves in a patriotic manner, writes Isaac Asabor.  Read more...

Submitted by
Black and White

We want to imitate the whites in everything because we are ignorant of our inherent originality and content. We spend all our Naira to acquire his inventions because we so oblivious of our natural endowments that we allow him have it for free. Read more...

Submitted by
Nate Nat
Adamawa State University Mubi: A ...

ADSU integrity forum has accused the Sunday Joshua Wugira, a lawyer, of adopting unorthodox tactics by abusing his privilege by attacking the integrity of ADSU Vice Chancellor Dr. Moses Zira Zaruwa, writes a News24 reader. Read more...

Submitted by
Abdulsalam Jubril
My Country Nigeria (Part One)

Poetry by Abdulsalam Jubril.

Submitted by
Abdulsalam Jubril
Recession, dearth in leadership a...

Every leader has the opportunity to become great and making himself immortal in the lives and hearts of people for generations to come. Will Mr. President seize this opportunity?, questions Abdulsalam Jubril. Read more...