Cortical thinness and volume differences associated with marijuana abuse in emerging adults. (1st October 2015)

• Record Type: Journal Article
• Authors: Mashhoon, Y.; Sava, S.; Sneider, J.T.; Nickerson, L.D.; Silveri, M.M.
• Is Part Of: Drug and alcohol dependence. Volume 155(2015)
• Page Start: 275
• Page End: 283
• Publication Date: 2015-10-01
• Subjects: Cortical thickness -- Volume -- Marijuana -- Young adults -- Thalamus -- Fusiform gyrus; Drug abuse -- Periodicals; Alcoholism -- Periodicals; 616.86
• DOI: 10.1016/j.drugalcdep.2015.06.016
• Languages: English
• ISSNs: 0376-8716

Abstract

Highlights: Used Freesurfer to measure cortical thickness and volume in emerging adult marijuana (MJ) users. Less cortical thickness in right hemisphere fusiform gyrus in MJ users vs. non-users. Smaller thalamic volume in MJ users, vs. non-users, related to greater impulsivity. RFG and thalamus may be connected through visual information processing pathway. Altered rFG and thalamus integrity may impair visuoperceptual processing in MJ users. Abstract: Background: The prevalence of marijuana (MJ) use among youth and its legalization for medical or recreational use has intensified public health endeavors of understanding MJ effects on brain structure and function. Studies indicate that MJ use is related to impaired cognitive performance, and altered functional brain activation and chemistry in adolescents and adults, but MJ effects on brain morphology in emerging adults are less understood. Methods: Fifteen MJ users (age 21.8 ± 3.6, 2 females) and 15 non-user (NU) participants (age 22.3 ± 3.5, 2 females) were included, demographically matched on age, education and alcohol use. High-resolution structural MR images were acquired at 3 Tesla. Cortical thickness (CT) and volumetric analyses were performed using Freesurfer. A priori regions of interest (ROI) included orbitofrontal and cingulate cortices, amygdala, hippocampus and thalamus. Results: Whole brain CT analysis did not result in significant group differences in a priori ROIs but revealed MJ users had significantly less CT (i.e., thinness) in right fusiform gyrus (rFG) compared to NU ( p < 0.05). Thalamic volume was significantly smaller in MJ users compared to NU (right, p = 0.05; left, p = 0.01) and associated with greater non-planning ( p < 0.01) and overall impulsivity ( p = 0.04). There were no other group differences. Conclusions: RFG cortical thinness and smaller thalamic volume in emerging adults is associated with MJ abuse. Furthermore, smaller thalamic volume associated with greater impulsivity contributes to growing evidence that the thalamus is neurobiologically perturbed by MJ use. Collectively, altered thalamic and rFG structural integrity may interfere with their known roles in regulating visuoperceptual and object information processing.