Study: Smoking Impacts 'Decision-Making' Part of Teens' Brains
Researchers at the University of California, Los Angeles found that teens who were the most addicted to nicotine had the least active prefrontal cortex regions of the brain, which control decision-making.
"It's another disturbing inconvenient truth," Lenox Hill Hospital pulmonologist Len Horovitz told AOL Health.
Scientists asked 25 smokers and 25 non-smokers between the ages of 15 and 21 to perform a well-known cognitive test called the Stop-Signal Task. The SST requires participants to press a button as fast as they can every time an arrow lights up. If an auditory tone is sounded, however, subjects must stop themselves from pressing the button.
The exercise gauges the ability to control or inhibit an action.
The authors of the study, which appears online in Neuropsychopharmacology, took MRI scans of the participants' brains while they were doing the test tasks. They also measured the level of the teens' addiction to nicotine with a questionnaire known as the Heaviness of Smoking Index, which asked not only how many cigarettes they smoked a day but how soon after waking they lit up.
Though the brain scans showed significantly less activity among the teenagers who were the most hooked on cigarettes, the two groups performed roughly the same on the action inhibitor test -- results the researchers didn't expect.
"The finding that there was little difference on the Stop-Signal Task between smokers and non-smokers was a surprise," study senior author Edythe London, a professor of psychiatry at the Semel Institute for Neuroscience and Human Behavior at UCLA, said in a statement. "That suggested to us that the motor response of smokers may be maintained through some kind of compensation from other brain areas."
But the lack of activity in the prefrontal cortex among the heaviest smoking teens was particularly alarming, since adolescents' delayed development in that area of the brain has been blamed for their poor decision-making abilities and weak cognitive control.
"Such an effect can influence the ability of youth to make rational decisions regarding their well-being, and that includes the decision to stop smoking," London said.
And modern-day teenagers are already on overload, so their distractedness has reached new heights, according to Horovitz.
"In the digital age, the powers of concentration on these kids are already not what they were in the previous generation," he said. "Impulse and impulse control are probably already underdeveloped, and smoking would accentuate that."
London said that while the immature prefrontal cortex is developing during adolescence, smoking might interfere with the process and have an impact on its function. A teen's already-underdeveloped brain could lead him to make a bad decision about starting to smoke -- and the act of smoking could further impair his cognitive control, causing him to continue the habit.
But the results of the SST were promising, suggesting that intervening early to stop a teen from taking up smoking may prove effective, according to London.
More than 400,000 deaths each year have been attributed to smoking cigarettes, the authors wrote. The habit usually forms during the teen years; 80 percent of adult smokers became dependent on nicotine by age 18.
Teenagers who don't smoke usually never start later in life, according to the findings.
Previous research has linked tobacco smoking with memory and cognitive problems in adults.
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