Link, clicky clicky

That article talks about depression and anxiety symptoms triggered by concussions. One of the highlights of it says:

Researchers using an MRI technique that measures the integrity of the brain’s white matter found unique white matter injury patterns in post-concussion patients who had depression or anxiety.

It is a unique MRI technique used to find it and they stated this damage would not show up on a normal MRI, and that depression patients who had concussions have normal results on an MRI in most cases.

There is also a possibility inflammation can be causing it, according to what I have read.

Another link, clicky clicky

This article explains research showing inflammation as a strong link. A highlight states:

A head injury can lead immune-system brain cells to go on “high alert” and overreact to later immune challenges by becoming excessively inflammatory – a condition linked with depressive complications, a new animal study suggests.

The findings could help explain some of the midlife mental-health issues suffered by individuals who experience multiple concussions as young adults, researchers say. And these depressive symptoms are likely inflammation-related, which means they may not respond to common antidepressants. I also read this on 'medicaldaily' in correlation to inflammation: A 2013 study in BMC Medicine reported inflammation was already on its way to being recognized as “a mediating pathway to both risk and neuro-progression in depression.”

I suppose it is something to consider.