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Antidepressant drugs may protect brain from damage due to depression

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  • Ian Pitchford
    Public release date: 1-Aug-2003 Contact: Nicole Vines vinesn@msnotes.wustl.edu 314-286-0105 Washington University School of Medicine Antidepressant drugs may
    Message 1 of 1 , Aug 1, 2003
      Public release date: 1-Aug-2003
      Contact: Nicole Vines vinesn@... 314-286-0105
      Washington University School of Medicine

      Antidepressant drugs may protect brain from damage due to depression

      St. Louis, Aug. 1, 2003 -- Studying women with histories of clinical
      depression, investigators at Washington University School of Medicine in St.
      Louis found that the use of antidepressant drugs appears to protect a key brain
      structure often damaged by depression.

      Previous research has shown that a region of the brain involved in learning and
      memory, called the hippocampus, is smaller in people who have been clinically
      depressed than in those who never have suffered a depressive episode. Now,
      researchers have found that this region is not quite as small in depressed
      patients who have taken antidepressant drugs.

      The study, led by Yvette I. Sheline, M.D., associate professor of psychiatry,
      radiology and neurology, appears in the August issue of the American Journal of
      Psychiatry. The hippocampus is a part of the brain's limbic system, a group of
      structures important to emotion and motivation. Using high-resolution magnetic
      resonance imaging (MRI), Sheline's team measured hippocampal volumes in 38
      women who had experienced an average of five episodes of major depression in
      their lifetimes. Only some of those episodes had been treated with
      antidepressant drugs.

      "In addition to their brain scans, each woman was interviewed on two occasions
      by independent interviewers to determine how long each depressive episode
      lasted and how much, if any, of that episode was treated with antidepressants,"
      Sheline says.

      The team compared hippocampal volumes to the number of days on or off
      treatment. They found that on average, hippocampal volume was smaller than
      normal in depressed women, and that the less time a woman had spent taking
      antidepressants, the smaller her hippocampus. The amount of volume loss was
      predictable, based on the number of days depressed versus the number of days on
      antidepressant treatment.

      "Our results suggest that if a woman takes antidepressants whenever she is
      depressed, depression would have less effect on the volume of her hippocampus,"
      Sheline says. "It is the untreated days that seem to affect hippocampal
      volumes."

      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 drugs prevent
      damage to hippocampal neurons or whether they may potentially restore
      previously lost volume. It is unclear whether drugs can restore volume that was
      lost, but she says this research demonstrates that without treatment,
      hippocampal volume loss in depressed patients was more extensive than it was in
      those who took antidepressant drugs.


      ###
      Sheline YI, Gado MH, Kraemer HC. Untreated depression and hippocampal volume
      loss. The American Journal of Psychiatry, vol. 160:6, pp. 1516-1518, Aug. 1,
      2003.

      This research was supported by grants from the National Institute of Mental
      Health and the Division of Research Resources of the National Institutes of
      Health.

      http://www.eurekalert.org/pub_releases/2003-08/wuso-adm072803.php
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