| Title: | Neuroanatomical Variability and Substance Use Initiation in Late Childhood and Early Adolescence |
| Authors: | Alex P. Miller, PhD, David A. A. Baranger, PhD, Sarah E. Paul, MA, Hugh Garavan, PhD, Scott Mackey, PhD, Susan F. Tapert, PhD, Kimberly H. LeBlanc, PhD, Arpana Agrawal, PhD, Ryan Bogdan, PhD |
| Year: | 2025 |
| Journal: | JAMA Network Open |
Introduction
Some studies have reported differences in brain structure in teens who use cannabis compared to those who do not. The question is: does cannabis cause such brain changes? Or did they exist before cannabis initiation, maybe signaling a vulnerability to drug use? This study looked at whether differences in the brains of teens who start using drugs, including cannabis are there from the beginning or if they develop because of drug use. Here we focus on the authors’ results specific to cannabis.
Methods
The researchers used data from the Adolescent Brain Cognitive Development (ABCD) Study, which tracked 9,804 kids aged 9–11 over several years. Each year, the kids reported if they had started using drugs, including cannabis. At the start, brain scans measured features like the size and thickness of certain brain areas. The team used advanced statistical methods to identify links between brain structure and cannabis use, while accounting for other factors like exposure to substances before birth.
Results
The study found that kids who started using cannabis had smaller right caudate volumes (a part of the brain involved in learning and memory, emotional regulation, response to rewards, as well as planning and execution of movement). Importantly, this was already true before they started using cannabis, suggesting that having a smaller right caudate might make some teens more likely to try cannabis, rather than cannabis use causing the brain change. 
Discussion
These results challenge the idea that all brain changes associated with cannabis use are caused by the substance itself. Instead, some differences might be developmental and make certain teens more likely to use cannabis or other drugs. More long-term studies are needed to better understand how brain differences and cannabis use are connected.
Read the full study here.
Citation: Miller AP, Baranger DAA, Paul SE, et al. Neuroanatomical Variability and Substance Use Initiation in Late Childhood and Early Adolescence. JAMA Netw Open. 2024;7(12):e2452027. doi:10.1001/jamanetworkopen.2024.52027