title: Brain Microstructure and Impulsivity Differ between Current and Past Methamphetamine Users.
abstract: Methamphetamine (Meth) use disorder continues to be highly prevalent worldwide. Meth users have higher impulsivity and brain abnormalities that may be different between current and past Meth users. The current study assessed impulsivity and depressive symptoms in 94 participants (27 current Meth users, 32 past Meth users and 35 non-drug user controls). Additionally, brain microstructure was assessed using diffusion tensor imaging (DTI); fractional anisotropy (FA) and mean diffusivity (MD) were assessed in the striatum, and FA, MD, radial and axial diffusivity were quantified in five white matter structures using DtiStudio.Across the three subject groups, current users had the highest self-reported impulsivity scores, while both Meth user groups had larger striatal structures than the controls. Past Meth users had the highest FA and lowest MD in the striatum, which is likely due to greater magnetic susceptibility from higher iron content and greater dendritic spine density. In white matter tracts, current Meth users had higher AD than past users, indicating greater water diffusion along the axons, and suggesting inflammation with axonal swelling. In contrast, past users had the lowest AD, indicating more restricted diffusion, which might have resulted from reactive gliosis. Although current Meth users had greater impulsivity than past users, the brain microstructural abnormalities showed differences that may reflect different stages of neuroinflammation or iron-induced neurodegeneration. Combining current and past Meth users may lead to greater variability in studies of Meth users. Longitudinal studies are needed to further evaluate the relationship between recency of Meth use and brain microstructure.
authors.affiliation: Neuroscience and MR Research Program, John A. Burn School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA.
authors.forename: Tamara
authors.initials: T
authors.lastname: Andres
authors.affiliation: Neuroscience and MR Research Program, John A. Burn School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ernst
authors.affiliation: Radiology and Radiological Sciences, Johns Hopkins Medicine, Baltimore, MD, USA.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Oishi
authors.affiliation: Neuroscience and MR Research Program, John A. Burn School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA.
authors.forename: David
authors.initials: D
authors.lastname: Greenstein
authors.affiliation: VA Pacific Islands Health Care System, Honolulu, HI, USA.
authors.forename: Helenna
authors.initials: H
authors.lastname: Nakama
authors.affiliation: Neuroscience and MR Research Program, John A. Burn School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA. lchang@hawaii.edu.
authors.forename: Linda
authors.initials: L
authors.lastname: Chang
mesh_terms: D000328:Adult; D019969:Amphetamine-Related Disorders / Q000000981:diagnostic imaging* / Q000523:psychology*; D001921:Brain / Q000000981:diagnostic imaging* / Q000187:drug effects*; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging / Q000639:trends; D005260:Female; D006801:Humans; D007175:Impulsive Behavior / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008694:Methamphetamine / Q000009:adverse effects*; D008875:Middle Aged
chemical_list: D008694:Methamphetamine
keywords: DTI; Impulsivity; Methamphetamine; Striatum; White matter