Heavy, chronic drinking can cause significant hippocampal tissue loss
The hippocampus, a brain structure vital to learning and memory, also appears vulnerable to damage from chronic, heavy alcohol consumption. A study of alcohol’s effects on the hippocampus has found that heavy drinking can reduce total hippocampus volume, which likely reflects a loss of hippocampal tissue substance. The results of the study are published in the November issue of Alcoholism: Clinical & Experimental Research.
“ The hippocampus actually refers to two structures, the right hippocampus and the left hippocampus that are located in the right and left temporal lobes of the brain,” explained Thomas P. Beresford, MD, professor of psychiatry and head of the Lab for Clinical Psych Research at the University of Colorado Denver, and a physician at the Department of Veterans Affairs.
“ Most scientists think that the hippocampus helps the brain manage learning, especially learning and remembering new things or things that happened recently. Before this study, researchers had noticed that the volume of the hippocampus seemed to be smaller in people who frequently drank large amounts of alcohol for long periods of time.” Beresford is also the corresponding author for the study.
“ The hippocampus is known to be injured by chronic stress and in Alzheimer's disease,” added Gary Wand, MD, professor of medicine and psychiatry, as well as director of the Endocrine Training Program at The Johns Hopkins University School of Medicine.
“ Although previous studies have shown a similar effect, this study was better controlled … making the findings more believable.”
Researchers used magnetic resonance imaging (MRI) scans to compare hippocampus volumes among adult male veterans who were both alcoholics (n=8) and non-alcoholics (n=8). All of the alcoholics had long, heavy drinking careers and were still drinking heavily at the time of the study.
“ Control” subjects were matched to the alcoholics by age and ethnicity.
“ We made a special effort in this study to include only people who did not have any of the things that other scientists think might make the hippocampus smaller, such as post-traumatic stress disorder,” said Beresford. “By excluding these people, we could focus only on the effects of chronic, heavy drinking.”
Study results indicate a reduction in total hippocampus volume among the alcoholics.
“ When we took a picture of the alcoholic brains using MRI, and measured the hippocampus,” said Beresford, “it was much smaller than the hippocampus in the group of people who did not drink alcohol heavily. This means that alcohol appears to injure the hippocampus by itself. That is, it may harm the hippocampus in a way that other things do not.”
