Cognitive dysfunction is a core and defining characteristic of schizophrenia (1). Countless cross-sectional studies, including in large population-based samples, have shown that IQ is lower in patients with schizophrenia, and lower than would be expected on the basis of the educational attainment of their mothers (2) and close relatives (3). The intellectual underperformance precedes the onset of psychosis by a decade (e.g., 4), with more recent longitudinal birth cohort data showing that the decline in IQ is progressive and starts in adolescence (5) if not earlier (6). Surprisingly, despite much more data being available, what happens after illness onset is less clear. Cross-sectional data provide a hint: IQ in schizophrenia patients is two standard deviations lower than that of healthy subjects in samples where IQ is assessed (many years) after illness onset, whereas it is only 0.5 standard deviations lower prior to diagnosis (7). Thus, one would expect IQ to continue to decline after psychosis onset. However, despite this large disparity in IQ deficits before and after psychosis onset, the cross-sectional data have not been confirmed in longitudinal studies (follow-up studies are needed in view of the confounders inherent to cross-sectional designs, such as cohort effects). This is not due to lack of trying: dozens of such studies have been done.
Iâm interested in this research particularly and
This quote âCross-sectional data provide a hint: IQ in schizophrenia patients is two standard deviations lower than that of healthy subjects in samples where IQ is assessed (many years) after illness onsetâ is plain wrong. 2 SD = IQ is around 70 for schizophrenic patient. Which is not true. There is no source for this statement too.
Zanelli effect size is -0.28 for a decade. Which means roughly 4-5 IQ Points per decade. So in order to reach 2 SDs you need to start being sick at the age of 20 and then your IQ should be measured at the age of 80.
Didnât like this paper.
I have no clue about the research study, but i know i lost a lot cognitively from the start of the illness, perhaps earlier too.
I suspect i have a very disharmonious profile now, in some areas gifted and in other areas mentally disabled. It is annoying, because people (myself too) overestimate me all the time, thinking im lazy or unwilling.
On some of my math exams I scored 2 sd below the mean and I studied hard. Maybe not smart but hard. I felt stupid and inferior. Looking back I was in the prodromal stages of schizophrenia for over a year or so. Went from straight As at community college to a 2.9 GPA at university. Felt like my IQ dropped 20 points. I once found an article where the average math major iq was 130. My doctorâs opinion was that my IQ was 110. Hence, I got a couple Ds and Fs on my tests yet still managed to passâŚ
Just felt like sharing my story. Not saying IQ is related to GPa or test scores. Maybe?
I worked my ass off. But the memory loss and confusion and â â â â made things hard and difficult to understand abstract and advanced topics. Told people I thought I had dementia. No one took it seriouslyâŚ
I call that a âspikyâ cognitive profile . It goes with being on the autism spectrum and /or having a learning disability(USA terminology).
You can often be seen as being obstructive , passive- aggressive(or as you say lazy) if you canât do something. When the reality is itâs in an area where your cognitive ability is weaker.
I do think the 2SD(30 point) decline is very high . It would mean an averagely intelligent person ending up being on the borderline of having what Americans call an âintellectual disabilityâ
Donât believe it after my first hard fall the creative works got very good.
Yes, that exactly, i was looking for words. People think im indifferent or even indeed obstructing. Or they give me these huge responsibilities and im just thinking âwaaaahh, what now??â. It is frustrating. They thought i was on the autism spectrum. And then they thought i wasnt. I dont know.
Disclaimer: I havenât read the full paper - only the excerpt given.
However, IQ is not taken seriously as a thing on itâs own these days. Neuropsychologists will do the old standard IQ tests like the WAIS, but only look at the relationship between scores within each subdomain. They will determine if a patient has cognitive decline based on if there are significant differences between scores on different domains. For instance attention may be poor but episodic memory good. They measure things like spatial memory, verbal memory, task switching, verbal reasoning etc. Then they factor in your educational attainment to see if there has been any cognitive decline.
Such a situation would point to someone having a learning difficulty(UK)/learning disability(USA)rather than necessarily overall cognitive decline .
I think in the USA people being dxed to see if they are on the autism spectrum are far more likely to have their cognition tested than in the UK. This is based on posts Iâve come across from people in the UK and USA.
Whether thatâs true of people with psychosis I donât know . The only things I can ever remember doing is digit span, and counting from 100 in groups of 7. That was when I was first hospitalised at 18. I also had a proverbs test a few months after that.