Friday, April 15, 2005

New Study Reveals Genetic Component to Nicotine Addiction

A study published in the current issue of Behavioral Neuroscience reports that researchers have identified genetic factors that may relate to susceptibility to nicotine addiction. According to the American Psychological Association press release on this article, "Understanding how genes change nicotine receptors may foster better treatments." Senior author, Dr. Jerry A. Stitzel from the University of Colorado, stated that: “By identifying genes that contribute to whether an individual will become addicted, we will gain important knowledge about the biology of addiction. With that, we will be in a much better position to design more effective treatments for addiction. This approach may also lead to treatments tailored to the ‘genetic profile’ of the smoker.”

This study is not the only one examining potential genetic factors in nicotine addiction. New Zealand researchers are apparently studying gene variants that may influence nicotine metabolism (and therefore addiction). They are apparently testing individuals for these genetic variants and have claimed that "Genetic tests based on this could enable personalised nicotine replacement therapy to be developed, making it more likely that it will be successful." Similar studies are ongoing elsewhere.

The Rest of the Story

While I'm all for tobacco research, I really don't see much value in this line of inquiry. Let's stipulate, for the purposes of argument, that there is indeed a very strong genetic influence on nicotine addiction. OK, so what should we be doing differently?

The research doesn't seem to have any useful implications for efforts to prevent smoking. Even if we were able to identify precisely those kids who are most at risk for becoming addicted, would we deliver our interventions only to those kids? There are so many factors, both genetic and environmental, that influence smoking initiation, that our interventions to prevent smoking will always have to be broad-based and targeted at a large segment of the (if not the entire) youth population. And I can't see doing genetic testing on kids to determine which ones will receive certain interventions. Most importantly, the interventions that have been found to be most effective in preventing smoking are societal-level, population-based interventions, not individually delivered ones.

Could the research have important implications for smoking cessation interventions? Again, the most successful interventions we have to encourage smoking cessation are population-based (such as aggressive marketing campaigns and smoke-free laws). It's not clear to me how even an individual-level intervention, such as nicotine replacement therapy, would be altered based on a genetic test to make a substantial difference in the effort to help smokers overcome their addiction. What is it that we can't already measure? For example, we already have ways of determining the strength of someone's addiction to nicotine. Usually, it's quite readily apparent. In fact, usually the smoker herself knows exactly what the strength of cessation difficulty is. I don't think there's anything that you couldn't ascertain from a simple, inexpensive, and carefully conducted interview with a smoker that you could ascertain from a fancy and expensive DNA test.

In short, I don't see any substantial value in this line of research into genetic susceptibility to nicotine addiction. It has no important implications for the practice of tobacco control, either for the prevention of smoking or the encouragement of smoking cessation. It does not seem to provide any essential information that we cannot already obtain if we are careful enough and take enough time to talk to our patients. It may be detracting from and/or reducing funds available for research that really does have important implications for public health policy and practice. And it may even help the tobacco industry in its litigation by allowing the companies to argue that genetic susceptibility, not corporate behavior, is the most salient factor in nicotine addiction (although that's not a reason to fail to conduct this research if it were otherwise important).

We really already have a very good idea of what works and what does not work in tobacco control. I think it's time that we start putting our money into implementing these proven strategies, rather than just doing more basic research to find out fancier and more expensive ways of ascertaining information that we can already find out, if we only are willing to take the time to talk to the affected individuals.

2 comments:

Jon said...

I agree.

From what I've seen of this sort of research, most of it can be characterized as one or more of:

1. physiologizing

2. sort-crossing

3. unlikely to add value to prevention or treatment

4. irrelevant; treats the problem at the wrong level

An analogy: if you don't like the lineup of TV shows, you don't

1. blame the man inside your TV set, and start looking for him

2. blame the electronics inside the set, and go at them with a hardware analyzer

3. ignore the known solutions to get better shows

4. pretend that the TV generates its programming

And if you do, you're likely only to waste your time.

A more direct criticism "genes that contribute to whether an individual will become addicted" have been swimming around in the gene pool for millions of years. It's only in the last 60 years that millions have become addicted to nicotine. The genes are not new. Mass manufacture, mass merchandizing, mass promotion, and mass consumption of nicotine delivery product is new. You're looking in the wrong place.

A specific example: check out the account of behavior in:

http://www.cleveland.com/living/plaindealer/index.ssf?/base/living/1113309000185600.xml

Now compare a simpler account, without intervening variables in CNS: repeated exposure to the substance changes behavior to seek the substance when the individual is under stress. Notice how the explanatory power of this account is EXACTLY THE SAME without positing brain events. It's not that the brain events don't happen; it's that they add nothing to the account.

A more general criticism: for 50 years it's been highly popular and funded in research circles to define, research, and attack smoking at the cell level. This approach has been unsuccessful.

It has been far more effective to define, research, and attach this problem at the social level: policy change, identifying and countering pro-smoking forces in society, attacking what actually spreads smoking. Brain and genetic research largely miss the point.

Now there's always hope that this sort of research will delivery a prophylactic for nicotine addiction, a vaccine for smoking. That's "tech fix" and the hope of it is always a pretty thing. But to date it's been little more than alluring.

In fact, we have a vaccine for smoking: it's called policy change, primary intervention. We have a vaccine for cancer. It works. We do not use it. By and large we don't fund it, we don't use what's known to work in smoking prevention, we cut it every day.

One reason we don't use the vaccine for cancer that we have: we downplay its effectiveness.

And possibly one reason behind that: we keep hoping for the tech fix.

Thus it's even possible that this sort of brain and gene research is worse than a waste of time; it may actually be diverting time, attention, funding, and resources from what works.

And one reason to suspect this is the case: tobacco industry research loves to define the problem at the cell level. Looking only at what happens with neurotransmitters is great for the industry: you never see $10 billion worth of Marlboro advertising in the synapse. You miss the point in a way the industry loves.

I also agree that defining the problem as individual differences plays into industry PR that the product is OK, it's just not for everyone. A cozy framing for the industry. Lethally incorrect for everyone else. A spectrum of harm doesn't mean it's harmless. Diversity of damage doesn't mean it's OK. A variety of responses doesn't mean it's not highly addictive slow poison. Accepting the industry's focus on individual differences plays into industry framing that obfuscates these key points.

Michael Siegel said...

Jon,
Thanks for adding these excellent comments. I especially appreciate your mentioning the issue of how we "frame" the issue. Emphasizing individual differences does frame this as a problem of individual behavior and supports the way the tobacco industry has been trying to frame the issue.
Mike