Dale Earnhardt, Jr.

When you have a concussion, one of the symptoms that is common is anxiety. Imagine having the normal amount of anxieties that everybody shares - about life and meeting people in social spaces, whatever. Imagine that being multiplied by 10, 20. And so your worry over people's perceptions of you multiplies.

I don't think any of us knew the dangers of repeated concussions or the fact that even when you got a concussion, the idea to go get treatment for it never entered our minds. We just didn't have - we weren't educated enough. We were really ignorant to it. I would get concussions in my early 20s racing, and it was a bit of a badge of honor.