Researchers observe brain differences in teens who use the drug once or twice

Teenagers who report using recreational marijuana just once or twice display increased volume of numerous brain regions, according to a study of 14-year-olds from Ireland, England, France, and Germany. The research, published in JNeurosci, warrants further study of low-level cannabis use among adolescents amid changing societal attitudes toward the drug.

Analyzing data from a large research program investigating adolescent brain development and mental health, Catherine Orr, Hugh Garavan, and colleagues identified brain regions rich in cannabinoid receptors that showed structural differences in teenagers who reported limited cannabis use. These differences persisted despite controlling for many variables, including sex and socioeconomic status as well as alcohol and nicotine use, and were only apparent after cannabis use. Finally, the researchers demonstrate associations between increased grey matter volume in low-level cannabis users and assessments of reasoning and anxiety.

Given the important role of the endogenous cannabinoid system in brain development during adolescence, teenagers may be particularly vulnerable to the effects of THC, the primary psychoactive component of marijuana. Additional research is needed to determine whether these findings apply to more diverse populations beyond the four European countries studied here.

###

Article: Grey Matter Volume Differences Associated with Extremely Low Levels of Cannabis Use in Adolescence

DOI: http://www. jneurosci. org/ lookup/ doi/ 10. 1523/ JNEUROSCI. 3375-17. 2018

Corresponding author: Catherine Orr (Swinburne University of Technology, Melbourne, Australia), corr@swin.edu.au

About JNeurosci

JNeurosci, the Society for Neuroscience's first journal, was launched in 1981 as a means to communicate the findings of the highest quality neuroscience research to the growing field. Today, the journal remains committed to publishing cutting-edge neuroscience that will have an immediate and lasting scientific impact, while responding to authors' changing publishing needs, representing breadth of the field and diversity in authorship.

About The Society for Neuroscience

The Society for Neuroscience is the world's largest organization of scientists and physicians devoted to understanding the brain and nervous system. The nonprofit organization, founded in 1969, now has nearly 37,000 members in more than 90 countries and over 130 chapters worldwide.