what is the primary effect of alcohol consumption on brain development before age 25?

The primary effect of alcohol consumption on brain development before adulthood is the disruption of critical developmental processes, particularly in the prefrontal cortex and hippocampus. Alcohol inhibits neuron growth and decreases myelination, which impairs the brain's ability to form and strengthen neural connections during adolescence. This disruption can lead to long-lasting or permanent changes, including reduced memory, learning capacity, and impaired judgment and decision-making skills. Adolescent brains are more vulnerable to alcohol's damaging effects compared to adult brains, and early alcohol use can reduce the size of the hippocampus by up to 10%, potentially causing irreversible deficits in brain function.