On Fri, 8 Aug 2003, Carrol Cox wrote:
> 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.
This is interesting research. Note, however, that the relationships among depression, hippocampal volume, and anti-depressant drug use are all correlational. Researchers typically make strong claims about cause and effect in science if they manipulate the causal factor and discover a change in the outcome. (In this case, perhaps randomly assign people to drug therapy or placebo and see if hippocampal volume differs over time.) The problem here is that there could be dozens of confounding variables (biological, social, economic factors) that account for the onset of depression, use of anti-depressants, and brain structure. Using this research to claim that antidepressants cause changes in the hippocampus is not good scientific reasoning (it's like saying that ice cream consumption must be a cause of crime because the level of ice cream consumption in a given day in the U. S. is predictive of the incidence of crime).
Miles