Altered white matter microstructure in adolescent substance users

Bava, Sunita; Frank, Lawrence R.; McQueeny, Tim; Schweinsburg, Brian C.; Schweinsburg, Alecia D.; Tapert, Susan F.

doi:10.1016/j.pscychresns.2009.04.005

« Previous Next »Psychiatry Research: Neuroimaging
Volume 173, Issue 3 , Pages 228-237, 30 September 2009

Altered white matter microstructure in adolescent substance users

Sunita Bava
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA
Lawrence R. Frank
- Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
Tim McQueeny
- VA San Diego Healthcare System, San Diego, CA 92161, USA
Brian C. Schweinsburg
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA
- Department of Psychiatry, Yale University, New Haven, CT 06511, USA
Alecia D. Schweinsburg
- Department of Psychiatry, Yale University, New Haven, CT 06511, USA
Susan F. Tapert
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA
- VA San Diego Healthcare System, San Diego, CA 92161, USA
- Corresponding author. VA San Diego Healthcare System, 3350 La Jolla Village Drive 116B, San Diego, CA 92161, USA. Tel.: +1 858 552 8585x2599; fax: +1 858 642 6474.

Received 2 December 2008; received in revised form 10 March 2009; accepted 9 April 2009.

Abstract

Chronic marijuana use during adolescence is frequently comorbid with heavy alcohol consumption and associated with CNS alterations, yet the influence of early cannabis and alcohol use on microstructural white matter integrity is unclear. Building on evidence that cannabinoid receptors are present in myelin precursors and affect glial cell processing, and that excessive ethanol exposure is associated with persistently impaired myelination, we used diffusion tensor imaging (DTI) to characterize white matter integrity in heavy substance using and non-using adolescents. We evaluated 36 marijuana and alcohol-using (MJ+ALC) adolescents (ages 16–19) and 36 demographically similar non-using controls with DTI. The diffusion parameters fractional anisotropy (FA) and mean diffusivity (MD) were subjected to whole-brain voxelwise group comparisons using tract-based spatial statistics (Smith, S.M., Jenkinson, M., Johansen-Berg, H., Rueckert, D., Nichols, T.E., Mackay, C.E., Watkins, K.E., Ciccarelli, O., Cader, M.Z., Matthews, P.M., Behrens, T.E., 2006. Tract-based spatial statistics: voxelwise analysis of multi-subject diffusion data. Neuroimage 31, 1487-1505). MJ+ALC teens had significantly lower FA than controls in 10 regions, including left superior longitudinal fasciculus (SLF), left postcentral gyrus, bilateral crus cerebri, and inferior frontal and temporal white matter tracts. These diminutions occurred in the context of increased FA in right occipital, internal capsule, and SLF regions. Changes in MD were less distributed, but increased MD was evident in the right occipital lobe, whereas the left inferior longitudinal fasciculus showed lower MD in MJ+ALC users. Findings suggest that fronto-parietal circuitry may be particularly impacted in adolescent users of the most prevalent intoxicants: marijuana and alcohol. Disruptions to white matter in this young group could indicate aberrant axonal and myelin maturation with resultant compromise of fiber integrity. Findings of increased anisotropic diffusion in alternate brain regions suggest possible neuroadaptive processes and can be examined in future studies of connectivity to determine how aberrancies in specific tracts might influence efficient cognitive processing.