The brains of adolescents who use substances are different from their peers who do not use substances.
That’s according to new research that found that brain structure metrics measured in late childhood, between ages 9 and 11, are associated with substance use in early life, before age 15. Therefore, differences in brain structure could partially demonstrate a predisposition for beginning substance use earlier in life.
Using substances at an early age has “potential cascading implications,” namely, an increased risk of developing a substance use disorder (SUD).
“In comparing participants who had initiated substance use in any form, including even just sips of alcohol or puffs of nicotine or cannabis products, to those who had not, we found that number of baseline brain structure differences,” Alex Miller, the study’s lead researcher, told Addiction Treatment Business in an email. “Variability in brain structure may partially reflect predispositional risk for initiating substance use earlier in life which is, in turn, associated with greater risk of developing a substance use disorder later in life.”
Miller is an assistant professor at Indiana University School of Medicine’s Department of Psychiatry.
The study used data from the Adolescent Brain Cognitive Development (ABCD) Study, a large, long-term study of brain development and child health funded by the National Institutes of Health (NIH). Researchers studied data from over 9,800 children to conclude that brain characteristics developed before substance use are associated with adolescents using substances early in their development.
Previous research has mainly focused on substance use’s impact on brains, according to Miller. This study instead investigated the effect of the brain on substance use.
Particularly notable among the study’s findings was that substance use at an early age was associated with larger brain measurements, including larger whole brain volume, greater cortical volume and surface area and greater subcortical structures. This is striking because SUDs developed in adulthood are associated with smaller global brain metrics.
Despite the study’s compelling findings, Miller cautions against using the findings in a clinical setting but said they do inform and challenge current theoretical addiction models.
“Given the design and limitations of the study, as with most studies of this type, it is premature to conclude that these differences are causing substance use initiation directly,” Miller said. “Rather, we conclude that they seem to at least partially precede initiation, and hopefully, this will inform future work that will continue to disentangle the nature of these associations.”
Future research could investigate the degree to which brain structure differences are influenced by genetic or environmental factors, as well as if patterns shift as the brain develops and children continue or stop using substances in adulthood.