Binge drinking is, unfortunately, most common among adolescents (12-20 years). But this is a time when brains are still developing. Does this make them more vulnerable to the detrimental effects of excessive alcohol?
A study involving adolescent mice has revealed that not only did an alcoholic binge reduce the activity of many neurotransmitter genes, but that gene expression in adulthood was even more seriously reduced. Although this deficit didn’t translate into problems with spatial learning, adult mice that had been exposed to excess alcohol in adolescence were significantly worse on a reversal learning task. Moreover, certain brain regions (the olfactory bulb and basal forebrain) were smaller.
In humans, it is thought that these impairments might translate into greater difficulty in adapting to changed situations, in evaluating consequences and controlling impulses.
Similarly, another recent study involving teenagers (15-21) has found that activity in the prefrontal cortex varied according to how heavily they smoked, with those who smoked most heavily having the least activity.
The 25 smokers and 25 non-smokers were tested on a Stop-Signal Task, which tests a person’s ability to inhibit an action. Despite the differences in activity level, smokers and non-smokers performed similarly on the task, suggesting that other brain areas are in some way compensating for the impaired prefrontal cortex. Nevertheless, reduced activity in the prefrontal cortex, which is still developing in adolescence, does suggest long-term consequences for decision-making and cognitive control.
(2011). Adolescent Binge Drinking Alters Adult Brain Neurotransmitter Gene Expression, Behavior, Brain Regional Volumes, and Neurochemistry in Mice.
Alcoholism: Clinical and Experimental Research. 35(4), 671 - 688.
(2011). Neural Correlates of Response Inhibition and Cigarette Smoking in Late Adolescence.
Neuropsychopharmacology. 36(5), 970 - 978.