title: Longitudinal changes in white matter microstructure after heavy cannabis use.
abstract: Diffusion tensor imaging (DTI) studies of cannabis users report alterations in brain white matter microstructure, primarily based on cross-sectional research, and etiology of the alterations remains unclear. We report findings from longitudinal voxelwise analyses of DTI data collected at baseline and at a 2-year follow-up on 23 young adult (18-20 years old at baseline) regular cannabis users and 23 age-, sex-, and IQ-matched non-using controls with limited substance use histories. Onset of cannabis use was prior to age 17. Cannabis users displayed reduced longitudinal growth in fractional anisotropy in the central and parietal regions of the right and left superior longitudinal fasciculus, in white matter adjacent to the left superior frontal gyrus, in the left corticospinal tract, and in the right anterior thalamic radiation lateral to the genu of the corpus callosum, along with less longitudinal reduction of radial diffusion in the right central/posterior superior longitudinal fasciculus, corticospinal tract, and posterior cingulum. Greater amounts of cannabis use were correlated with reduced longitudinal growth in FA as was relatively impaired performance on a measure of verbal learning. These findings suggest that continued heavy cannabis use during adolescence and young adulthood alters ongoing development of white matter microstructure, contributing to functional impairment.
authors.affiliation: Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, MN 55455, United States; Center for Neurobehavioral Development, University of Minnesota, 717 Delaware Street SE, Ste. 333, Minneapolis, MN 55414, United States. Electronic address: petr0308@umn.edu.
authors.forename: Mary P
authors.initials: MP
authors.lastname: Becker
authors.affiliation: Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, MN 55455, United States; Center for Neurobehavioral Development, University of Minnesota, 717 Delaware Street SE, Ste. 333, Minneapolis, MN 55414, United States.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Collins
authors.affiliation: Department of Psychiatry, University of Minnesota, 2450 Riverside Avenue South, Minneapolis, MN 55454, United States.
authors.forename: Kelvin O
authors.initials: KO
authors.lastname: Lim
authors.affiliation: Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, MN 55455, United States.
authors.forename: R L
authors.initials: RL
authors.lastname: Muetzel
authors.affiliation: Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, MN 55455, United States; Center for Neurobehavioral Development, University of Minnesota, 717 Delaware Street SE, Ste. 333, Minneapolis, MN 55414, United States.
authors.forename: M
authors.initials: M
authors.lastname: Luciana
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000187:drug effects; D017668:Age of Onset; D000437:Alcoholism / Q000150:complications / Q000473:pathology; D016880:Anisotropy; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000473:pathology* / Q000523:psychology; D008568:Memory / Q000187:drug effects; D011597:Psychomotor Performance / Q000187:drug effects; D014706:Verbal Learning / Q000187:drug effects; D066127:White Matter / Q000473:pathology* / Q000648:ultrastructure; D055815:Young Adult
keywords: Cannabis; DTI; Longitudinal; White matter; Young adult