Neurocognitive correlates of white matter quality in adolescent substance users

Brain Cogn. 2010 Apr;72(3):347-54. doi: 10.1016/j.bandc.2009.10.012. Epub 2009 Nov 22.

Abstract

Background: Progressive myelination during adolescence implicates an increased vulnerability to neurotoxic substances and enduring neurocognitive consequences. This study examined the cognitive manifestations of altered white matter microstructure in chronic marijuana and alcohol-using (MJ+ALC) adolescents.

Methods: Thirty-six MJ+ALC adolescents (ages 16-19) and 36 demographically similar controls were evaluated with diffusion tensor imaging (Bava et al., 2009) and neurocognitive tests. Regions of group difference in fractional anisotropy (FA) and mean diffusivity (MD) were analyzed in relation to cognitive performance.

Results: In users, lower FA in temporal areas related to poorer performance on attention, working memory, and speeded processing tasks. Among regions where users had higher FA than controls, occipital FA was positively associated with working memory and complex visuomotor sequencing, whereas FA in anterior regions was negatively associated with verbal memory performance.

Conclusions: Findings suggest differential influences of white matter development on cognition in MJ+ALC using adolescents than in non-using peers. Neuroadaptation may reflect additive and subtractive responses to substance use that are complicated by competing maturational processes.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adolescent
  • Adolescent Development / drug effects
  • Alcoholism / complications
  • Alcoholism / pathology*
  • Alcoholism / psychology
  • Case-Control Studies
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / growth & development
  • Cerebral Cortex / pathology*
  • Cognition Disorders / etiology
  • Cognition Disorders / pathology*
  • Cognition Disorders / psychology
  • Cohort Studies
  • Drug Users / psychology
  • Female
  • Humans
  • Male
  • Marijuana Abuse / complications
  • Marijuana Abuse / pathology*
  • Marijuana Abuse / psychology
  • Nerve Fibers, Myelinated / drug effects
  • Nerve Fibers, Myelinated / pathology*
  • Neuropsychological Tests
  • Reference Values
  • Young Adult