title: Grey Matter Changes Associated with Heavy Cannabis Use: A Longitudinal sMRI Study.
abstract: Cannabis is the most frequently used illicit drug worldwide. Cross-sectional neuroimaging studies suggest that chronic cannabis exposure and the development of cannabis use disorders may affect brain morphology. However, cross-sectional studies cannot make a conclusive distinction between cause and consequence and longitudinal neuroimaging studies are lacking. In this prospective study we investigate whether continued cannabis use and higher levels of cannabis exposure in young adults are associated with grey matter reductions. Heavy cannabis users (N = 20, age baseline M = 20.5, SD = 2.1) and non-cannabis using healthy controls (N = 22, age baseline M = 21.6, SD = 2.45) underwent a comprehensive psychological assessment and a T1- structural MRI scan at baseline and 3 years follow-up. Grey matter volumes (orbitofrontal cortex, anterior cingulate cortex, insula, striatum, thalamus, amygdala, hippocampus and cerebellum) were estimated using the software package SPM (VBM-8 module). Continued cannabis use did not have an effect on GM volume change at follow-up. Cross-sectional analyses at baseline and follow-up revealed consistent negative correlations between cannabis related problems and cannabis use (in grams) and regional GM volume of the left hippocampus, amygdala and superior temporal gyrus. These results suggests that small GM volumes in the medial temporal lobe are a risk factor for heavy cannabis use or that the effect of cannabis on GM reductions is limited to adolescence with no further damage of continued use after early adulthood. Long-term prospective studies starting in early adolescence are needed to reach final conclusions.
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Laura
authors.identifier: 0000-0001-9382-7872
authors.initials: L
authors.lastname: Koenders
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.|Addiction Development and Psychopathology (ADAPT)-lab, Department of Developmental Psychology, University of Amsterdam, Amsterdam, The Netherlands.|Department of Developmental Psychology and Psychonomics, Utrecht University, Utrecht, The Netherlands.
authors.forename: Janna
authors.initials: J
authors.lastname: Cousijn
authors.affiliation: Department of Nuclear Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.|Department of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
authors.forename: Wilhelmina A M
authors.initials: WA
authors.lastname: Vingerhoets
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: van den Brink
authors.affiliation: Addiction Development and Psychopathology (ADAPT)-lab, Department of Developmental Psychology, University of Amsterdam, Amsterdam, The Netherlands.|Cognitive Science Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Reinout W
authors.initials: RW
authors.lastname: Wiers
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Carin J
authors.initials: CJ
authors.lastname: Meijer
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Marise W J
authors.initials: MW
authors.lastname: Machielsen
authors.affiliation: University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
authors.forename: Dick J
authors.initials: DJ
authors.lastname: Veltman
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.|Arkin Mental Health Care, Amsterdam, The Netherlands.
authors.forename: Anneke E
authors.initials: AE
authors.lastname: Goudriaan
authors.affiliation: Department of Psychiatry, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Lieuwe
authors.initials: L
authors.lastname: de Haan
mesh_terms: D000328:Adult; D002188:Cannabis; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D002189:Marijuana Abuse; D055815:Young Adult