Posted by Larry Hoover on December 30, 2008, at 17:58:36
In reply to Re: Actually, that's not what the study found., posted by linkadge on December 30, 2008, at 15:47:17
> But, the fact that TCA use is associated with significant white matter loss suggests there is some link between antidepressants and white matter loss. I.e. what is the mechanism by which TCA's accelerate white matter loss?
No, not necessarily. If factor A leads to outcomes B and C, B and C will be correlated, although they are otherwise independent. The study authors themselves raised the idea that TCAs may be prescribed more often for severe depression, "Finally, participants may be prescribed TCAs if their depression is more severe, and such individuals may have more severe cerebrovascular disease."
In discussing limitations of the study, the authors also say, "These (limitations) include the relatively small sample size of individuals on antidepressants, as well as the lack of data on why participants were taking them and for what duration....We are also unable to capture interval development and course of depression during this time period."
So, until they can systematically assess (and adjust for) the influence of depression per se, and its time course, the correlation between antidepressants and white matter loss is unexplained.
As I said, IMHO, the report raises questions, but answers none.
Lar
poster:Larry Hoover
thread:871107
URL: http://www.dr-bob.org/babble/20081223/msgs/871470.html