Sorry to say that there is some imaging evidence showing physical atrophy in several sections of the brain that accompany major, chronic depression. I'm not sure, but I believe the areas include the amygdala and prefrontal cortex among others. I also believe that these changes have been shown to be reversible for the most part.

I know that my multitasking ability is gone, my decision making ability is not nearly as good, and my mental acuity is not as good as it was. I'll hunt around and see if I can come up with the sources for these claims, but I feel pretty good (or bad) about what I've written.

I'll get back soon...
DJ