Animal studies also have demonstrated that antidepressant drugs can protect against stress-induced decreases in hippocampal volumes. Why the hippocampus shrinks is not clear. It may be that brain chemicals released during depression, such as cortisol, damage brain cells. Or it could be that depression damages the connections between nerve cells, resulting in a smaller volume. But however the damage is done, Sheline says it is clear from this study that antidepressant drugs can limit volume loss.
"We've shown in other studies that people with hippocampal damage also have problems with certain memory tests," she says. "And large epidemiology studies have shown that major depression is a risk factor for the later development of Alzheimer's disease. So it seems clear that volume loss in the hippocampus can have very negative effects, not to mention the devastating problems caused by depression itself."
Sheline and colleagues did not look at specific antidepressants to compare whether one was better than another at preserving hippocampal volumes, but any antidepressant seems to protect the brain better than no treatment.
Sheline says because volume loss in the hippocampus appears to be cumulative -- that is, the more episodes of depression, the more volume loss -- it is important to recognize and treat depression right away to prevent damage. It also may be worthwhile for patients to continue taking antidepressants between episodes of depression.
"Many psychiatrists already recommend that some patients who are prone to depression remain on antidepressants permanently to protect against depression," Sheline explains. "These apparent neuroprotective effects provide a further argument for at least strongly considering remaining on antidepressants."
Currently, Sheline's team is looking at whether antidepressant dr
'"/>
Contact: Nicole Vines
vinesn@msnotes.wustl.edu
314-286-0105
Washington University School of Medicine
1-Aug-2003