Well, I don't know about brain injury at all. But I know I don't have euphoric mania but dysphoric mania, which means mania is not fun or "high" for me, just speeded up and aggitated all the time.

I think there is hope tho with the right treatment. The goal is not have depressionor mania. I know a lot of people like mania because of euphoria. But the goal is to be as close to stable as possible.