I played junior high and high school football. I had two concussions during that time, one serious enough to make me feel a shift in my temperment and just made me feel hazy and depressed for the years following. I remember having dizzy spells and being made fun of by teammates and being regarded as weak because I hated contact after that. I stuck it out until the end, but I hated football all during that time. I always felt that those head injuries had long term effects on me; I just didn't feel as sharp as I should. Over time I got used to it, but now, in my early thirties I have noticed things like a slight tremor and feel anxiety more than I used to. With the link of head trauma and neurodegenerative disorders, I can't help but feel that those concussions were somewhat of a contributing factor.
I do know that every person's experience is different and that some bodies will be more susceptible than others. I have a history of alzheimers in my family, so I don't know if that predisposition to neurodegenerative disease puts me at higher risk to effects of head trauma, or not. That is something research will teach us. Further, as medical science progresses, treatments for things like ALS, Parkinsons, and CTE seem to be just upon the horizon. I love watching football and I would never question any parent's decision to allow their own child to make their own choice. However, because of my experience, I will not allow my kids to play contact sports.