The sleeper effect of a single cigarette: why "just once" spells bad news for your brain, your body, and future addiction.

Can just one cigarette at age 11 create a lifelong vulnerability for addiction?

Posted Jul 30, 2010

The New York Times recently ran a piece about preventing children and teens from starting to smoke. The title of the piece said it all: "Not Starting Means Never Having to Quit."

It reminded me of a little-known but startling study from 2006, published in Tobacco Control -- a journal you're not likely to read unless you have a keen interest in, well, tobacco control (or perhaps tobacco marketing and sales, but let's not be too cynicial).

This study, conducted by researchers at the Department of Epidemiology and Public Health at University College London, followed 5863 adolescents from age 11 to 16. Each year, they asked the kids about their smoking habits, including whether or not they had ever tried a cigarette. The researchers also took saliva samples to measure nicotine levels.

What they found was remarkable: a 3-year "sleeper effect" for tobacco addiction. That is, a single cigarette can create "a personal propensity or vulnerability to smoke that may not become manifest without additional triggers."

What was the evidence that lead to this claim? The researchers discovered that an adolescent who had smoked just one cigarette at age 11 was twice as likely to be a regular smoker at age 14 than those who had not tried a cigarette at age 11. This was true even for the kids who did not smoke again in the intervening years.

The researchers created a breakdown of how many adolescents went from being "one time triers" to current regular smokers each year:
• 16% of grade 7 "one time triers" became current smokers for the first time in grade 8 (age 12-13), compared with only 3% of grade 7 never-smokers.
• 18% of grade 7 "one time triers" became current smokers for the first time in grade 9 (age 13-14), compared with only 7% of grade 7 never-smokers. (This is on top of those who converted the year before.)
• Finally, another 20% became current smokers in grade 10 (age 14-15), compared with 10% of grade 7 never-smokers. For these "later" converters, no smoking had been reported (beyond the initial grade 7 cigarette) in the intervening years.

The researchers interpreted these findings as suggesting that a single cigarette can create a "dormant vulnerability" that may take years to express itself.

The researchers carefully considered and ruled out possible alternative explanations related to why a kid at eleven might be more likely to try smoking. The sleeper effect held true even if you controlled for gender, ethnicity, socioeconomic status, parents' smoking, and conduct problems. It wasn't that the early experimenters were destined to smoke because of their backgrounds and personalities. Something about the early experience added a major risk factor.

Was the dormant vulnerability biological, psychological, or social? This study wasn't designed to answer this question. But as the researchers note, it's possible one cigarette could trigger all three. The researchers speculated that a single smoking experience -- especially at such a young age - could alter areas of the brain associated with learning, reward, and addiction. Nicotine and all of the other sensory cues associated with smoking could become coded into the brain as a stress reliever or reward. Future stress, boredom, or social anxiety might then interact with the dormant biological vulnerability, and increase the chances that the adolescent will turn to cigarettes.

A single smoking experience at such a young age might also increase the chances that an adolescent will identify him or herself as a smoker, and feel close to other smokers. Smoking may become a bond with other "adventurous" kids, or brand an adolescent within his social group as a risk-taker. And any further educational or social pressures not to smoke may be less effective once the adolescent has made that initial "transgression."

The researchers argue that preventing early smoking experimentation should be an important policy goal. Even delaying a first cigarette might reduce population-level smoking rates.

These findings may be a clue to a much broader phenomenon: that early exposure to addictive substances or activities, from high-fat foods and alcohol to gambling and video games, may create lasting vulnerabilties.
As a child growing up under the watchful glare (I mean, gaze) of overprotective parents, I didn't think much of their child-rearing strategies. But as research teaches us more about how early life experiences powerfully shape future addiction, I'm starting to appreciate the lockdown!

J A Fidler, J Wardle, N Henning Brodersen, M J Jarvis, R West. Vulnerability to smoking after trying a single cigarette can lie dormant for three years or more. Tobacco Control 2006;15:205-209. doi:10.1136/tc.2005.014894.

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