I recently found a link to a website with information relating to the connection between concussions and suicidal depression. The website gives information on the correlation between people who have suffered concussions and the high percentage rate of those victims who also end up suffering from anxiety, memory loss, change in personality and eventually depression.
The site is hosted by Bill Brown and also has information and a link of where to purchase a video he recently made on this topic, titled The Hidden Epidemic.