A new study found distinct differences in brain structure between individuals who reported substance use before age 15 and those who did not. Many of these structures seemed to exist before substance use began, indicating that they may play a role in the initiation of substance use later in life. The findings were published in JAMA Network Open.
Early substance use is linked to a higher risk of developing substance use disorders later in life. Until now, however, the neuroanatomical variability linked to early substance use has remained relatively unknown. In the current study, researchers thus sought to identify neuroanatomical features linked to early substance use and how much associations may predict pre-existing vulnerability.
To do so, they analyzed data from 9804 participants from the US between the ages of 9 and 11 years old in 2016- 2018 and then again three years later. Data included MRI scans and self-reported substance use. Altogether, 3,460 participants reported initiation of substances- including alcohol, nicotine, and cannabis- before age 15, and 6,344 did not.
Various differences in brain structure were identified between those who reported substance use before age 15 and those who did not, including greater total brain volume and subcortical volume at the global level alongside 39 structural differences at the regional level, around 56% of which involved cortical thickness. Cannabis use, in particular, was linked to lower right caudate volume.
In another analysis, the researchers found that many of these differences remained after removing participants who reported substance initiation prior to their baseline MRI scans. This suggests that some of the observed structural differences may have existed before any substance use.
Further research is now needed to understand how initial brain structural differences may change over time, especially alongside continued substance use or the development of a substance use disorder.
"The hope is that these types of studies, in conjunction with other data on environmental exposures and genetic risk, could help change how we think about the development of substance use disorders and inform more accurate models of addiction moving forward,” said corresponding study author Alex Miller, Ph.D., an assistant professor of psychiatry at Indiana University, in a press release.
Sources: News-Medical.net, JAMA Network Open
