A study funded by the National Institutes of Health (NIH) examined nearly 10,000 adolescents to identify brain structure differences in those who used substances before age 15 compared to those who did not. The findings suggested that some structural brain differences existed in childhood before any substance use, indicating a potential role in the risk of substance use initiation later in life. This research, alongside genetic, environmental, and other neurological factors, may help understand an individual’s level of risk and resilience for substance use and addiction.
The study found that among the adolescents who initiated substances before age 15, most reported trying alcohol, with overlap in nicotine and/or cannabis use. Substance initiation was associated with brain-wide structural differences primarily in the cortex, some of which were substance-specific. While these findings could potentially inform prevention strategies, researchers caution that brain structure alone cannot predict adolescent substance use and should not be used as a diagnostic tool.
The research, published in JAMA Network Open, used data from the Adolescent Brain Cognitive Development Study (ABCD Study), the largest longitudinal study of brain development and health in children and adolescents in the United States. Researchers from Washington University in St. Louis analyzed MRI scans of participants aged 9 to 11 to determine if brain structure captured in early scans was associated with early substance initiation. They compared MRIs of 3,460 participants who initiated substances before age 15 to those who did not, assessing global and regional brain structure differences.
The study identified several global and regional brain structural differences between those who initiated substances before age 15 and those who did not. The findings included differences in total brain volume, subcortical volume, and cortical thickness. Some of these structural differences were unique to the type of substance used. A post-hoc analysis indicated that many of these brain differences persisted even when participants who initiated substances after their baseline MRIs were removed, suggesting some structural differences may exist prior to any substance use.
While some of the identified brain regions have been associated with sensation-seeking and impulsivity, further research is needed to understand how these structural differences may affect brain function and behaviors. The researchers emphasize the complex interplay between genetics, environment, brain structure, and behavior in influencing substance use. Future studies will explore how initial brain structure differences may change with aging and continued substance use, aiming to improve models of addiction and inform prevention efforts.
Through the ABCD study, researchers aim to understand the bidirectional relationship between brain structure and substance use, alongside environmental exposures and genetic risk. Data from the study could help change the understanding of substance use disorders and improve models of addiction. Continued research will be crucial in determining how brain structure differences evolve over time and the impact of continued substance use on brain development.
