When I was at university, I got an IQ score of 120. My GPA at the end was 3.67 which was a A- in American speak, but 67% 2:1 in UK speak.
Since I have not been able to read.
I did an IQ test about a year ago and scored 80 
Not sure what has happened
My intelligence I think has taken a battering, but there are some ways it still shows, but disappointedly absent in my measures
My academic performance,but not necessarily my IQ, started to decline after getting mumps at the age of 9. I was a mediocre student at public school. It didn’t help that my study habits were far from good. I don’t think having a serious mental illness has changed things,to any noticeable degree, re my IQ.
I performed very well in academics…high school valedictorian and college magna cum laude. Unfortunately, it took me longer to get mental health aid as everyone figured that since I was doing so well in school then nothing could be really wrong with me.
Schizophrenia is linked with both pre and post morbid changes. Premorbid iq is also a predictor of functional outcome. So that’s one of the best tools to have in your recovery toolkit.
I remember seeing one study that said the average decline was 13 iq points. Intelligence stays pretty stable overtime so if your iq really was 120 then would think it would be unlikely but not impossible that your iq dropped 40 points. Were both tests administered by a doctor/psychologist? If not then the results weren’t valid.
Also I think it is hard to reliably test iq in schizophernia especially if you were experiencing positive symptoms at the time of the test for example.
That aside the functional impact is probably much greater then 13 iq points anyway
There’s a positive symptom called ‘thought blocking’ which can be temporary and can mimic a fall in IQ. I had it a lot during my transition to psychosis but bounced back from it fairly well.
I was straight A’s till I hit 14 around puberty. Lost most of my math pretty quickly and survived on a still good memory. I tend to think it was indicitive of underlying problems namely that insidious paranoia but didn’t get dxed till 29. Most kids thought I was on drugs at that time of late high school although I just smoked cigs.
I was very probably 2e but back then,early 1960s to mid 1970s, there was no help and support for it. Ditto the bullying I was subjected to for being different. My housemaster at public school said,in so many words, that I was the kind of boy that lent himself to being bullied. Some people do well when under pressure/stressed, I’m not one of those.
In fact I’m the complete opposite. Looking back the combination of unrecognised 2e and the stress caused by being bullied was a perfect storm for academic underachievement , and a factor in developing SMI.
@NutsAboutU Good point!
@rogueone Yeah the kids used to say the same thing at my high school except they were too young to even know how drugs affected you. Likewise, I think it was indicative of divergent thinking/ my sense of humour. I think that it’s quite common that mostly people get dxed quite late as the signs are not immediately obvious to others from the outside.