Is there a "predisposition to drug addiction"? Scientists answer

The main question that concerned the researchers was: does the brain really change under the influence of substances, or does its original structure itself increase the likelihood of early use?

Source:

Alex P. Miller et al. "Neuroanatomical Variability and Substance Use Initiation in Late Childhood and Early Adolescence," JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.52027

Felix Pichardo et al, The Adolescent Brain Cognitive Development Study and How We Think About Addiction, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2024.51997

As part of the work published in JAMA Network Open, experts studied data from more than 9,800 children aged 8,9-11 years (at the start of follow-up) from 22 research centres in the United States. The study was conducted over three years, and scientists tracked which participants started using alcohol, nicotine, cannabis or other substances before the age of 15. In parallel, MRI scans of the brain were carried out to determine its volume and structural features in different areas.

The results showed that children prone to early use often exhibited some characteristic features of brain structure: larger total brain volume, enlarged hippocampus and globus pallidum, and thinner cortex in the frontal lobes, especially in the middle frontal gyrus. Interestingly, all of these differences were detected even before the adolescents started trying alcohol or cigarettes. This suggests that a number of children have an innate "vulnerability" that makes them more susceptible to early use.

Approximately 35 per cent of participants admitted to starting to use any substance before the age of 15. The most common substance involved was alcohol (about 90 per cent of cases). Scientists emphasise that such data are important for understanding the mechanics of teenage addictions and forming prevention strategies. If structural features of the brain do influence the propensity to experiment with illegal or dangerous substances, it could change the way we look at the nature of addiction and approaches to therapy.

In an accompanying commentary, experts from the University of Minnesota note that the scope and design of the study (including genetic measurements and observations of the twins) make it possible to very reliably separate pre-existing factors from substance-induced changes.

These results are consistent with another recent study that reached similar conclusions regarding the link between adolescent cannabis use and psychotic symptoms.

Thus, the discovered facts indicate: not only do substances "reshape" the brain, but the structure of the brain itself may initially set the stage for earlier experimentation with alcohol and drugs.