I had a similar injury (head trauma resulting in sub-dermal hematoma and concussion) that preceeded my worst depressive episode. I was already "in" a depressive episode and my motor skills were not very responsive which is why i hit my head in the first place, but after I hit it I almost immediately spiraled downward. Depression became *almost* unbearable and I have been moderately unstable since...although I am finally feeling stable again just over the past couple of months, minus one hypomanic episode : ).

So, while I don't know for sure if it could have caused your foundation to be rocked, I know that circumstantially, it seems as though the events line up for me and I can hypothesize that they may have lined up for you, too. I am glad you are finding stability again and that your back injury healed fully. It IS disheartening, however, that medical professionals would only treat the injury that seems the most severe and neglect to address all parts of your injury, namely your TBI.