People who start smoking in their mid-teens may have less gray matter in two brain regions that play a central role in pleasure-seeking, self-control, and risk-taking. Analyzing brain imaging data from over 800 people aged 14, 19, and 23, researchers discovered that both the left and right ventromedial prefrontal cortex (vmPFC) appeared smaller in those who took up cigarettes at a young age.
The vmPFC is a key node in the cortico-mesolimbic dopaminergic system and regulates various aspects of cognitive function, including risk assessment and response inhibition. It’s thought that deficits within this brain region may be linked to unhealthy behaviors such as binge drinking and drug abuse.
After examining brain scans and behavioral information relating to hundreds of young people in the UK, Ireland, France, and Germany, researchers noted that those who began smoking as teenagers had less gray matter in their left vmPFC at age 14 than those who didn’t use cigarettes. In their write-up, the study authors explain that reduced gray matter in this part of the brain may lead to “behavioral disinhibition due to the discounting of consequences of rule-breaking,” thereby making youngsters more likely to smoke.
“In our study, reduced grey matter in the left prefrontal cortex is associated with increased rule-breaking behavior as well as early smoking experiences,” explained study author Trevor Robbins in a statement. “It could be that this rule-breaking leads to the violation of anti-smoking norms,” said Robbins.
Noting this association, the researchers say that this trait may represent an “inheritable biomarker” for nicotine addiction. In contrast, they found that reductions in gray matter volume within the right vmPFC only occur after the initiation of smoking, suggesting that cigarette use triggers a loss of function within this part of the brain.
At baseline, smokers and non-smokers displayed similar gray matter volumes within the right vmPFC, although accelerated shrinking was then noted from the age of first cigarette use in smokers. Given that this part of the brain plays a central role in thrill-seeking, the authors say that “following this initiation of smoking, the reduced [gray matter volume] in the right vmPFC may subsequently sustain and thus strengthen smoking behavior further by removing inhibitory constraints on reward seeking and heightening the hedonic experience of smoking.”
Summarizing these findings, lead study author Professor Tianye Jia explained that “less gray matter in the left frontal lobes is linked to behaviors that increase the likelihood of smoking in adolescence.”
“Smokers then experience excessive loss of grey matter in the right frontal lobes, which is linked to behaviors that reinforce substance use. This may provide a causal account of how smoking is initiated in young people, and how it turns into dependence.”
The study is published in the journal Nature Communications.
Source Link: Teenage Smoking Linked To Reduced Gray Matter In Key Brain Regions
