title: Gray-matter volume in methamphetamine dependence: cigarette smoking and changes with abstinence from methamphetamine.
abstract: BACKGROUND
  Group differences in brain structure between methamphetamine-dependent and healthy research participants have been reported, but findings in the literature present discrepancies. Although most methamphetamine-abusing individuals also smoke cigarettes, the effects of smoking on brain structure have not been distinguished from those of methamphetamine. Changes with abstinence from methamphetamine have also been relatively unexplored. This study, therefore, attempted to account for effects of smoking and brief abstinence from methamphetamine on gray-matter measures in methamphetamine-dependent research participants.
  
  
  METHODS
  Gray matter was measured using voxel-based morphometry in three groups: 18 control nonsmokers, 25 control smokers, and 39 methamphetamine-dependent smokers (methamphetamine-abstinent 4-7 days). Subgroups of methamphetamine-dependent and control participants (n=12/group) were scanned twice to determine change in gray matter over the first month of methamphetamine abstinence.
  
  
  RESULTS
  Compared with Control Nonsmokers, Control Smokers and Methamphetamine-dependent Smokers had smaller gray-matter volume in the orbitofrontal cortex and caudate nucleus. Methamphetamine-dependent Smokers also had smaller gray-matter volumes in frontal, parietal and temporal cortices than Control Nonsmokers or Smokers, and smaller gray-matter volume in insula than control nonsmokers. Longitudinal assessment revealed gray matter increases in cortical regions (inferior frontal, angular, and superior temporal gyri, precuneus, insula, occipital pole) in methamphetamine-dependent but not control participants; the cerebellum showed a decrease.
  
  
  CONCLUSIONS
  Gray-matter volume deficits in the orbitofrontal cortex and caudate of methamphetamine-dependent individuals may be in part attributable to cigarette smoking or pre-morbid conditions. Increase in gray matter with methamphetamine abstinence suggests that some gray-matter deficits are partially attributable to methamphetamine abuse.
authors.affiliation: Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90024, USA.
authors.forename: Angelica M
authors.initials: AM
authors.lastname: Morales
authors.forename: Buyean
authors.initials: B
authors.lastname: Lee
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hellemann
authors.forename: Joseph
authors.initials: J
authors.lastname: O'Neill
authors.forename: Edythe D
authors.initials: ED
authors.lastname: London
mesh_terms: D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000473:pathology* / Q000523:psychology; D001921:Brain / Q000473:pathology*; D002421:Caudate Nucleus / Q000473:pathology; D000697:Central Nervous System Stimulants; D002540:Cerebral Cortex / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D005917:Globus Pallidus / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008694:Methamphetamine; D008875:Middle Aged; D017072:Neostriatum / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology; D012907:Smoking / Q000473:pathology* / Q000523:psychology; D013375:Substance Withdrawal Syndrome / Q000523:psychology; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D008694:Methamphetamine