This is a compilation of my POIS. Onset must've been in puberty. As I didn't abstain till 2019 when I 1st saw O giving brainfog, etc..
Symptoms: Brainfog-head feels heavy/empty, as if engine has dust, need to focus more to recall, hard to read, when reading/hearing sometimes must manually focus on meaning rather than meaning processing simultaneously, tend to daydream, can think less step ahead e.g. in chess. Narrow eyesight-I see best what eyes directly look at, eye pressure. Voice change-volume's lower, tend to not engage tongue to pronounce words clearly by default. Weaker-less stamina. Worse reflex/clumsier.
Other info:
As kid had milk intolerance-got diarrhea, green poop, spots on face from, sleeptime cramps (epilepsy (appeared at ~2 years)) which got put under control by antiepileptics early on, took antiepileptics till 15 when I took lowdose safest SSRI to transition away from meds as cramps got cured (EEG showed too). Had near-pneumonia at 6 years, temp got 40c, got antibiotic, fixed it. Hit head at 7 years on ground outside playing in automatic fountain as 2 older girls run into me, had headache days after, afair no other symptom.
Mild OCD at 11, went away from 14-17, now back, POIS might've appeared with it but 1st didn't got bad symptoms, had ocd-like face/vocal tic symptoms in combo with it, elevated by stress at 14. Still get sometimes urge to move face/make noise in a way but only for few sec unlike back then. I think it started when I felt body more during stress, felt uncomfortable, low latent inhibition (mind doesn't filter out stimuli, e.g. in home I hear all stuff without focusing).
When I had throat pain, compulsive cough, mucus above lungs I had 1 NE, 2 O 0POIS so immunity's related to it.