Date of Award

May 2018

Degree Type


Degree Name

Master of Science



First Advisor

Krista M Lisdahl

Committee Members

Christine L Larson, Han Joo Lee


Nicotine use is still widely prevalent among adolescents and young adults. Nicotine use is associated with white matter microstructural changes as measured by diffusion tensor imaging (DTI), a magnetic resonance imaging technique that measures the diffusion of water in the brain. In adults, nicotine use is generally associated with poorer white matter microstructure, exhibiting lower fractional anisotropy (FA), but in adolescents/young adults, microstructure appears healthier, as indicated by higher FA. No study has examined gender differences in the effects of nicotine on white matter microstructure in young adults. 53 subjects (18 nicotine users [10 female] and 35 controls [17 female]) underwent an MRI scan, neuropsychological battery, toxicology screening, and drug use interview. Nicotine group and gender*nicotine group were used to predict FA and mean diffusivity (MD) in various white matter tracts. In significant tracts, axial (AD) and radial (RD) diffusivity were measured. Nicotine users exhibited significantly lower FA than controls in the left anterior thalamic radiation, left inferior longitudinal fasciculus, left superior longitudinal fasciculus—temporal, and left uncinate fasciculus. In these tracts, AD and RD did not differ, nor did MD differ in any tract. The gender*nicotine group interaction did not predict any diffusion measures. These results are inconsistent with other adolescent/young adult studies, likely due to methodological differences and a slightly older sample. Further studies should examine the longitudinal effects of nicotine use and gender in a larger sample.

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