“The maturation of the brain is still ongoing in adolescence, and especially the frontal areas and the cingulate cortex develop until the twenties. Our findings strongly indicate that heavy alcohol use may disrupt this maturation process,” said first author of the study Noora Heikkinen from University of Eastern Finland.
Cingulate cortex has an important role in impulse control, and volumetric changes in this area may play an important role in the development of a substance use disorder later in life.
The study — published in the journal Addiction — performed magnetic resonance imaging (MRI) of the brain structure on young and healthy, but heavy-drinking adults who had been heavy drinkers throughout their adolescence, as well as on age-matched light-drinking control participants.
They participated in three cross-sectional studies conducted over the course of ten years, in 2005, 2010 and 2015. The participants were 13 to 18 years old at the onset of the study.
All participants were academically successful, and the prevalence of mental health problems did not differ between the two groups.
Although the heavy-drinking participants had used alcohol regularly for ten years, approximately six-nine units roughly once a week, none of them had a diagnosed alcohol use disorder.
MRI of the brain revealed statistically significant differences between the groups.
Among the heavy-drinking participants, grey matter volume was decreased in the anterior cingulate cortex bilaterally as well as in the right insula.
While cingulate cortex has an important role in impulse control, structural changes in the insula, on the other hand, may reflect a reduced sensitivity to alcohol’s negative subjective effects, and in this way contribute to the development of a substance use disorder.