title: Cigarette exposure, dependence, and craving are related to insula thickness in young adult smokers.
abstract: The age period spanning late adolescence to emergent adulthood is associated with the highest prevalence of cigarette smoking in the United States, and is also a time of continued brain development. Nonetheless, although prior research has shown group differences in brain structure associated with smoking status in adults, few studies have examined how smoking and associated behavioral states relate to brain structure in this age group. Neuroimaging and lesion studies have suggested that the insula, a cortical region that integrates heterogeneous signals about internal states and contributes to executive functions, plays an important role in cigarette smoking behavior. Using high-resolution structural magnetic resonance imaging, we therefore measured cortical thickness of the insula in 18 smokers and 24 nonsmokers between the ages of 16 and 21 years. There were no group differences in insula thickness, but cigarette exposure (pack-years) was negatively associated with thickness in right insula. Cigarette dependence and the urge to smoke were negatively related to cortical thickness in the right ventral anterior insula. Although the results do not demonstrate causation, they do suggest that there are effects of cigarette exposure on brain structure in young smokers, with a relatively short smoking history. It is possible that changes in the brain due to prolonged exposure or to the progression of dependence lead to more extensive structural changes, manifested in the reported group differences between adult smokers and nonsmokers. Structural integrity of the insula may have implications for predicting long-term cigarette smoking and problems with other substance abuse in this population.
authors.affiliation: 1] Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, USA [2] Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA [3] Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Angelica M
authors.initials: AM
authors.lastname: Morales
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Dara
authors.initials: D
authors.lastname: Ghahremani
authors.affiliation: 1] Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, USA [2] Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA [3] Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Milky
authors.initials: M
authors.lastname: Kohno
authors.affiliation: Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Gerhard S
authors.initials: GS
authors.lastname: Hellemann
authors.affiliation: 1] Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, USA [2] Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, USA [3] Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA.
authors.forename: Edythe D
authors.initials: ED
authors.lastname: London
mesh_terms: D000328:Adult; D002540:Cerebral Cortex / Q000473:pathology*; D066249:Craving; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012907:Smoking / Q000473:pathology* / Q000523:psychology; D014029:Tobacco Use Disorder / Q000473:pathology* / Q000523:psychology; D055815:Young Adult