Well, I have had three major concussions in my life. When I was around 12 my cousin accidentally slammed the boot of my uncles car on my head. I went down fast. I was a psychological mess all day. Laughing, crying - for no reason. Second was a boating accident at age 17. Luckily I didn't totally pass out as I would of drowned. Third is embarrassing. I was the teller at the front desk of a health fund. My handbag was under the counter. I went to grab something out of it and then thought I heard the door open. I was alone at the counter so I rushed my head up to serve the customer. Instead I smashed my head on the bottom of the counter and knocked myself out. That concussion was the worst and I was off work for days.

Anyway, None of these incidents were followed by episodes and my BP symptoms started in my early teens according to my pdoc. I guess it's possible but it would have to be rare.