Reduced frontal cortical thickness and increased caudate volume within fronto-striatal circuits in young adult smokers

Effect of tobacco smoking on frontal cortical thickness development: A longitudinal study in a mixed cohort of ADHD-affected and -unaffected youth

“…Our main finding of a thinner frontal cortex in smokers is in line with previous reports describing CT and volume differences between smokers and non-smokers (Durazzo et al, 2013; Kühn et al, 2010; Li et al, 2015; Wang et al, 2015; Zhong et al, 2016). We also observed a relationship between smoking and total CT, which is in agreement with more widespread effects found in earlier studies (Wang et al, 2015).…”

“…Other studies used cortical thickness (CT) as an outcome measure, which has been argued to be a more specific and sensitive measure for gray matter loss than VBM (Kühn et al, 2010). In accordance with the VBM studies, smokers exhibited lower CT in the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and insula, and also more extensively across the frontal, temporal and parietal lobes (Durazzo et al, 2013; Karama et al, 2015; Kühn et al, 2010; Li et al, 2015). Taken together, less gray matter in various brain regions has been observed in relation to smoking, but most consistently in the prefrontal cortex (Wang et al, 2015).…”

“…Of the frontal regions that we distinguished, the effect of smoking was strongest in the right orbitofrontal cortex (OFC). Notably, in two earlier studies, OFC volume correlated negatively with magnitude of tobacco exposure, implying a dose-dependent effect (Kühn et al, 2010; Li et al, 2015). Smaller OFC volumes have also been linked to other forms of substance use (e.g., Lotfipour et al, 2009; Smith et al, 2015; Tanabe et al, 2009), and the role of the OFC in addiction is further substantiated by a myriad of functional neuroimaging findings showing that OFC activity varies with drug expectation, craving, and addiction severity (Goldstein and Volkow, 2011; Jasinska et al, 2014).…”

“…Two other studies, in middle-aged and elderly samples, did not observe associations of smoking with changes in global gray matter volume over periods of four and five years respectively (Duriez et al, 2014; Van Haren et al, 2010). This is perhaps not surprising, considering the fact that neurotoxic effects may vary between regions (Dwyer et al, 2009), with striatal regions often found to be unaffected or even larger in smokers (Das et al, 2012; Li et al, 2015). In agreement with this, we found no significant effect of smoking on total gray matter volume.…”

Functional Connectivity of the Raphe Nuclei: Link to Tobacco Withdrawal in Smokers

“…To help clarify the role of serotonin on the relationship between tobacco withdrawal and connectivity of the median raphe nuclei, future studies could examine effects of serotonergic medications on withdrawal symptoms and associated changes in brain function. As the participants were exclusively young smokers with short smoking histories and mild-to-moderate levels of nicotine dependence, as expected from smokers within this age range (e.g., Li et al, 2015; Bi et al, 2017; Faulkner et al, 2017), the results may not be generalizable to the wider population of smokers. Also, the small sample size and uneven gender distribution made it difficult to examine the influence of sex.…”