Tobacco addiction in adolescents could be explained as a vicious circle caused and fed back by the reduction of gray matter in the prefrontal cortex, a part of the brain associated with the control of the most primitive instincts. People who start smoking at a young age are genetically inherited with less gray matter on the left side of that brain area and a greater tendency to break rules, according to a study published Tuesday in Nature Communications. Once consumption begins, nicotine in turn reduces the volume of the right side and decreases the ability to control, anchoring the addiction.
For some time now, scientific evidence has pointed to the prefrontal cortex as the region that “fails a person who has an addiction”, whether to tobacco or cocaine, explains Mª Cristina Pinet, a psychiatrist from the Addictions Unit, in conversation with La Vanguardia. from the Hospital de Sant Pau (Barcelona), who did not participate in the research. The novelty of the study, points out the expert, is the interdisciplinary crossover and the precision of the results, which differentiate causes and consequences of addiction in the left and right sides of the prefrontal cortex, respectively.
The work, led by the universities of Cambridge and Warwick, in the United Kingdom, and Futan University, in China, analyzed the brain images and behavior of more than 800 young Europeans at three different ages: at 14, 19 and 23. years. Those who started smoking between the ages of 14 and 19 had previously shown a lower volume of gray matter in the left prefrontal cortex, the result of genetic inheritance, and a greater tendency to break the rules.
In other words, adolescent smokers had different biological and behavioral characteristics than non-smokers, even before having any contact with tobacco. The scientists hypothesize that a smaller volume of gray matter on the left side of the prefrontal cortex increases a teen’s impulsiveness, which in turn increases the likelihood that she will start smoking at a young age.
These previous changes do not occur on the right side of the prefrontal cortex. The size of this hemisphere changes once the adolescent has started smoking, so the researchers suggest that it is nicotine consumption that reduces the volume of gray matter in the right half of the brain. This maldevelopment alters, in turn, the way in which the individual seeks pleasure and decreases his ability to control, anchoring the addiction to tobacco.
Thus, while the left side of the prefrontal cortex can naturally facilitate the first contact with tobacco, nicotine artificially alters the right side to make it addictive. Smoking is, therefore, continuously feeding itself.
This reduced volume in the right hemisphere, and above all the lower associated control capacity, “confirms the hypothesis that smoking is a gateway to the consumption of other substances”, values ??Carles Soriano-Mas, principal researcher of the Psychiatry group and Mental Health of the Biomedical Research Institute of Bellvitge (IDIBELL), in reference to drug use.
That is why the expert, also a professor in the Department of Social and Quantitative Psychology at the University of Barcelona (UB) advocates early prevention and treatment. “If you direct this behavior of breaking the rules to other objectives, such as more artistic activities, this would prevent these people from approaching the world of drugs”, he develops.
For now, neuroimaging techniques and genetic analysis are too expensive to screen all adolescents, acknowledges Trevor Robbins, director of research at the Institute for Clinical and Behavioral Neuroscience at the University of Cambridge, and one of the authors of the study. study. Instead, measuring the tendency to break the rules “would be relatively easy.” According to their results, behavior is as good a predictor of smoking as are the other indicators.
