In Paris, €5.90 will buy you one the following: conditioner, flip flops, a mozzarella sandwich or a single pack of Lucky Strike cigarettes. Beyond the opulent architecture and elegant skyline, smoke was the first thing I noticed as I wandered the picturesque streets of my new home. Cigarettes in the hands of teenagers, waiters, lawyers, mothers, and ironically, and even medical students with immunology textbooks tucked under their arms. When I asked a local friend about his general smoking habits, his response surprised me:
Well, I guess the first time I tried it was when I was 12 – all my friends were doing it after all. Now, I just need to smoke… if I don’t, I get anxious and irritated.
Twelve-years old and already smoking, how could that be possible? However, my Parisian friend is not alone. In fact, according to CDC studies, among daily smokers, 88% begin before the age of 18 (National Center, 2012). With such a large well-known body of evidence detailing the physiological and psychological consequences of tobacco and nicotine, why would a teenager reach for a cigarette in the first place?
Age of Onset of Smoking
The “big picture” mechanisms of smoking seem pretty straight forward. Cigarettes contain tobacco, which in turn contains nicotine, which in turn triggers the addiction process. Addiction, or compulsive use of a substance in the face of negative consequences, is characterized by four distinct stages: introduction, sensitization, association/craving and dependence (Herman et al., 2014). However, the reasons behind why adolescents like the chain-smoking Parisian teens in particular are so vulnerable to nicotine are less understood.
One recent theory, published in Neuroscience by researchers Bang and Commons, examined the role of nicotine on the adolescent serotonin system. Serotonin (aka 5-HT) is a chemical released by neurons in the brain, and may contribute to starting and continuing addictive behavior. Based on previous research, Bang and Commons (2011) hypothesized that if they gave adolescent subjects nicotine, there would be changes in the activation of their serotonin neurons.
In the experiment, the researchers used eight groups of rats total – four with adolescents and four with adults. For both ages, three of the groups served as experimental (test) groups, and each group member received an injection of a specific dose (amount) of nicotine (0.2, 0.4, 0.8 mg/kg). The fourth group served a baseline/control group and received saline (salt water) instead of nicotine.
After humanely killing the animals, the researchers cut frontal slices each rat brain and used a process called immunohistochemistry to chemically mark the brain for specific proteins. The researchers specifically stained and measured the amount of Fos protein in brain areas important in the serotonin system (dorsal raphe and median raphe nuclei). The Fos protein corresponds to biochemical activity, so if nicotine changed or increased activity in the serotonin system, the researchers would observe increased Fos levels in comparison to the normal levels of the saline control group.
When comparing the adolescent and adult group, the researchers concluded that adolescents showed an increased, widespread activation of their brain serotonin system at the lowest (0.2mg/kg) and highest nicotine dosage (0.8mg/kg). On a larger scale, these results indicate that the adolescent serotonin system may be more sensitive to an initial exposure to nicotine. Though there needs to be more research defining the serotonin system’s role in addiction, this study helps elucidate the science behind adolescent nicotine vulnerability.
Arrows Indicate Fos Staining
Somehow, (and for the sanctity of my lungs) we need to stop teens from trying cigarettes in the first place. Based on the failure of smoking bans in France and the amount of smokers I saw on a daily basis, this is easier said than done. Research indicates that pervasiveness and social support of smoking in adolescent social networks is strongly associated with both susceptibility AND readiness to quit (Roberts et al., 2015). To relate to my own experience, none of my friends at home or on the trip smoke, so it was easy to turn down a cigarette when I was offered.
These are ALL Tobacco Shops in Paris
In the future, perhaps France should take after the example of the highly successful American “Truth” association, which uses the celebrity-endorsed #FINISHIT social media campaign to raise awareness about teen smoking. Until then, I’ll concede to duck around smoke clouds and spend my €5.90 on some much needed fabric Fabreze.
References:
Bang SJ, Commons KG (2011) Age-dependent effects of initial exposure to nicotine on serotonin neurons. Neuroscience 179:1-8.
Herman Al. DeVito EE, Jensen KP, Sofuoglo ME (2014) Pharmacogenetics of nicotine addiction: role of dopamine. Pharmacogenomics 15(2):221-34.
Khan, Maria. “France: First Outdoor Public Smoking Ban in Paris Playground.” International Business Times. 20 Oct. 2014. Web. 7 Jun. 2015.
National Center for Chronic Disease Prevention and Health Promotion (US) Office on Smoking and Health. Preventing Tobacco Use Among Youth and Young Adults: A Report of the Surgeon General. Atlanta (GA): Centers for Disease Control and Prevention (US); 2012. 3, The Epidemiology of Tobacco Use Among Young People in the United States and Worldwide.
Roberts ME, Nargiso JE, Gaitonde LB, Stanton CA, Colby SM (2015) Adolescent social networks: general and smoking specific characteristics associated with smoking. J Stud Alcohol Drugs 76(2):247-55
Truthorange. “Finshers 2014 | truth.” Online video clip. Youtube. Youtubem 10 Aug. 2014. Web. 7 Jun. 2015.