Oh wow, life suddenly makes much more sense me. I’m 25 now- diagnosed with PANDAS at 7 (was part of one the first studies in Boston) but I always used to have issues in the summer. I LOVED swimming but was always confused by my own behavior. I’d be a fairly social kid most of the time but was struck harder with my OCD, antisocial, severe anxiety symptoms (not all of them but I wonder if chlorine was a trigger for these more than others) during the summers.
If it’s any consolation, now I swim at the Y (heavily chlorinated haha) and often feel extremely calm after (I think just the mindfulness for swimming) so I think maybe chlorine makes it worse when the immune system is already freaking out or less developed (childhood, antibiotics). I still get PANDAS symptoms and am trying to work on finding triggers but chlorine isn’t one anymore. But thank you for helping me connect some more of the dots!