This was probably the earliest symptom that started impacting me, about three years before mine was discovered. I also fell into the same boat thinking ADHD related, though being in my forties, I found myself asking "why now?" It was probably the most mysterious and vexing symptom for me for a long time - I had blood/hormone/vitamin panels all run, monitored sleep, etc. Most of my symptoms were disguised by the fact that I document live music from within the pit 3-5 nights a week, so dehydration, interrupted sleep patterns, exposure to loud music and occasional kicks or punches to the face seemed more likely causes for brain fog, chronic fatigue, lightheadedness, loss of hearing (ironically, my suggesting an MRI to my doctor just to rule out undiagnosed concussions was how we found it relatively early (mine is specifically a VS at 15mm). I've found various things can influence it, such as barometric pressure or stress - and sometimes simply taking asprin with ibuprophen provides greater clarity than adderall - taking meticulous notes on a variety of factors helps me identify potential triggers and ways to mitigate.
