Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Feb 1;176(2):119-128.
doi: 10.1176/appi.ajp.2018.17040415. Epub 2018 Oct 19.

Mega-Analysis of Gray Matter Volume in Substance Dependence: General and Substance-Specific Regional Effects

Affiliations

Mega-Analysis of Gray Matter Volume in Substance Dependence: General and Substance-Specific Regional Effects

Scott Mackey et al. Am J Psychiatry. .

Erratum in

  • Correction to Mackey et al.
    [No authors listed] [No authors listed] Am J Psychiatry. 2019 May 1;176(5):414. doi: 10.1176/appi.ajp.2019.1765correction. Am J Psychiatry. 2019. PMID: 31251087 No abstract available.

Abstract

Objective: Although lower brain volume has been routinely observed in individuals with substance dependence compared with nondependent control subjects, the brain regions exhibiting lower volume have not been consistent across studies. In addition, it is not clear whether a common set of regions are involved in substance dependence regardless of the substance used or whether some brain volume effects are substance specific. Resolution of these issues may contribute to the identification of clinically relevant imaging biomarkers. Using pooled data from 14 countries, the authors sought to identify general and substance-specific associations between dependence and regional brain volumes.

Method: Brain structure was examined in a mega-analysis of previously published data pooled from 23 laboratories, including 3,240 individuals, 2,140 of whom had substance dependence on one of five substances: alcohol, nicotine, cocaine, methamphetamine, or cannabis. Subcortical volume and cortical thickness in regions defined by FreeSurfer were compared with nondependent control subjects when all sampled substance categories were combined, as well as separately, while controlling for age, sex, imaging site, and total intracranial volume. Because of extensive associations with alcohol dependence, a secondary contrast was also performed for dependence on all substances except alcohol. An optimized split-half strategy was used to assess the reliability of the findings.

Results: Lower volume or thickness was observed in many brain regions in individuals with substance dependence. The greatest effects were associated with alcohol use disorder. A set of affected regions related to dependence in general, regardless of the substance, included the insula and the medial orbitofrontal cortex. Furthermore, a support vector machine multivariate classification of regional brain volumes successfully classified individuals with substance dependence on alcohol or nicotine relative to nondependent control subjects.

Conclusions: The results indicate that dependence on a range of different substances shares a common neural substrate and that differential patterns of regional volume could serve as useful biomarkers of dependence on alcohol and nicotine.

Keywords: Mega-Analysis; Structural MRI; Substance-Related Disorders.

PubMed Disclaimer

Figures

FIGURE 1.
FIGURE 1.. Cortical Regions of Interest Exhibiting Substance- Specific or Shared Substance-General Effects Displayed on the Surface of Partially Inflated Average Brainsa
a Substance specific: alcohol alone (green), alcohol and cocaine (purple); substance general: pattern 2 (yellow), pattern 3 (orange).
FIGURE 2.
FIGURE 2.. Different Contributions of Dependence on the Five Substances Studied to the Association of Lower Volume or Thickness With Substance Dependencea
a For illustration purposes, both halves of the data (serving as the discovery and replication datasets) have been combined in the bar graphs. Three different patterns are illustrated. In pattern 1 (substance-specific effect), lower volume in the right nucleus accumbens was largely accounted for by dependence on alcohol alone. In pattern 2 (substance-general effect), volume in the left supramarginal gyrus was significantly lower in dependent compared with nondependent individuals (model 1) but was not significantly lower in any one particular substance group (model 2) compared with control subjects. In pattern 3 (substance-general effect), volume in the left insula was lower when either the alcohol-dependent group or the linear contrast of all substance groups except alcohol was compared with nondependent control subjects. Bars represent estimated marginal means expressed as percent difference from mean volume or thickness in nondependent control subjects. Error bars represent standard error. Meth=methamphetamine.
FIGURE 3.
FIGURE 3.. Plot of Receiver Operating Characteristic Curves for the Support Vector Machine Classification of Individuals Dependent on One of Five Substances Relative to Nondependent Control Subjectsa
aThe area under the curve (AUC) is significant for alcohol or nicotine dependence when trained on the first half of the data and tested on the second half (left) as well as when trained on the second half and tested on the first half (right). Meth=methamphetamine.

References

    1. Whiteford HA, Degenhardt L, Rehm J, et al.: Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010. Lancet 2013; 382: 1575–1586 - PubMed
    1. US Department of Health and Human Services: The Health Consequences of Smoking: 50 Years of Progress: A Report of the Surgeon General. Atlanta, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014
    1. World Health Organization (WHO): WHO Report on the Global Tobacco Epidemic 2011. Geneva, WHO, 2011
    1. Sacks JJ, Gonzales KR, Bouchery EE, et al.: 2010 national and state costs of excessive alcohol consumption. Am J Prev Med 2015; 49: e73–e79 - PubMed
    1. National Drug Intelligence Center: National Drug Threat Assessment. Washington, DC, US Department of Justice, 2011

Publication types

MeSH terms

Substances