The size of the hippocampus varies from one person to another regardless of depression, much like height and foot size vary. Several studies indicate that genetics determines about half of the size variation in the hippocampus.

so yes depression is assoc with a smaller hippocampus--but delayed treatment shows might be assoc with further shrinage--and the study shows antidepressants have been shown to stop further shrinage.

its like what came first chicken or egg .

the brain shrinks for everyone 1.9 % every 10 yrs then 1% every yr over 64 ---here the point yes it plausable in a larger % of chromic depression that the area of the hippocampus shrinks but seems to stop once medicated most eveidence appears it comes from the stress hormone released that does this damage.

white matter --is composed of nerve fiber

grey matter is made up of cell bodies

what has been studied in people with know depression and changes in brain images of people changing going thru dramatic life events --divorce,illness ,loss of job ,death of love ones --show shrinkage-- after these events--- where before areas were larger ---then it led me to ? if its just the way depressed ppl brain is like if ur born with it-- if thats the case why does it stop or changes with medication. That why i think it complicated. It not the same like a brain shows perm damage as it does with alheimzers or huntingtons .