Alcohol abuse is a risk factor for many health problems including metabolic, hepatic and neurological disorders, especially when chronic abuse begins in adolescence. Mounting evidence continues to support the conclusion that the developing brain of adolescence is particularly vulnerable to metabolic insults such as alcohol and illicit drug exposure.
A study was conducted by Michael D. De Bellis and his colleagues to correlate alcohol abuse in adolescents with the volume of a brain structure called the hippocampus. The hippocampus is critical for long term memory formation and retention and undergoes rapid development during adolescence.
In this study, hippocampal volumes in 12 adolescent subjects with an average age of 17 years, and a history of alcohol abuse, were compared to 24 healthy adolescents without a history of alcohol abuse. MRI images of the brains of both groups were assessed.
The hippocampal area was significantly smaller in all of the 12 subjects with alcohol use disorder as compared to the healthy controls. In addition, the earlier the onset of the alcohol use disorder positively correlated with the size of the hippocampus and negatively with the duration (in years) of the disorder. Other brain structures did not differ in size. Clinical examination of the subjects was not done in this study so it is not known whether the smaller size of the hippocampus led to a change in neurological function.
This is another study demonstrating evidence for neurological harm from chronic alcohol abuse. Alcohol may exert its effects through the inhibition of the N-methy-D-aspartate (NMDA) receptors with subsequent disinhibition and over-excitation once alcohol is removed. One theory posits that the inhibition of the NMDA receptors sets into motion several excitatory pathways that leads to a neuron-necrotizing response in the developing brain, but not in the mature brain. Chronic alcohol exposure in animals shows a similar detrimental effect on the hippocampal structures of the brain.
Citation: Hippocampal Volume in Adolescent-Onset Alcohol Use Disorders
Michael D. De Bellis, Duncan B. Clark, Sue R. Beers, Paul H. Soloff, Amy M. Boring, Julie Hall, Adam Kersh, and Matcheri S. Keshavan
American Journal of Psychiatry 2000 157:5, 737-744
