How can bobby fischer's cognition and intelligence be so high if he suffered from schizophrenia?

the iq test was done under official conditions by a top defence industry firm.

     The term "schizophrenia" was first used in a scholarly lecture by Swiss psychiatrist Eugen Blueler (a colleague of Freud and Jung) in 1908, although it had been used by German psychiatrists amongst themselves for a little while previously. It was meant to be a more precise substitute for the previously-used "dementia praecox", a condition that had first been described around the turn of the 18th/19th century.

     It is a Latinization of Greek words meaning "split" and "mind", as it seems that perception, memory, and cognition had been disconnected in the subjects' brains. The German and Swiss originators of the diagnosis felt that it is caused by a physical malfunction in the brain.

     The reason that Fischer could play so well was that he wasn't schizophrenic. (Nor did he ever claim to have an IQ of 180.)

there are three main types of illness or beastialities, they are amorphus to the images we see of animals, i am not sure of the physical processes, but one is catlike in that they seek to control their environment which is out of control ie hyper, one is dog like in that they interfere with themselves emotionally and seek to control others so that everyone is like themselves ie depressives. and one is birdlike in that they seek lack of a controlling environment thus they're thinking is unchained by reality, ie schizoid.  Like i stated the schizoids out of control mind allows for counter-productive and contradictory thinking causing delusions and confuscions but if the mind realises that these are contradictions the llack of control of the thought processes can lead to extreme creativity. And yes Fischer was a schizoid and intelligent. I think those that think schizoids are dum are deluding themselves that they have some kind of knowledge on the issue.

@30
 "And yes Fischer was a schizoid and intelligent. "
++ No to schizo, yes to intelligent.

deluded

I know for fact a psychiatrist examined fischer aged 25 and said he was a schizoid.

@32
Which psychiatrist? Source?
Psychiatrist Magnús Skúlason discussed with Fischer in Iceland and stated:
"He definitely was not schizophrenic".

@34
"he had issues though for sure"
++ Yes
https://psmag.com/social-justice/a-psychological-autopsy-of-bobby-fischer-25959 

I have hallucinatory problems, it makes playing chess very difficult as the board will warp and I'll see pieces or ideas that just plain aren't there and are outright impossible. I'll play solid one game, then find everything collapsing another simply because my brain decided to sleep in and I'm stuck trying to fight through brain fog and constant confusion and paranoia. Doesn't mean all schizophrenics would be totally impaired, but often if they have talent it manifests in bizarre ways in whatever field of interest they have. Who was that programmer... Terry Davis, I think. Brilliant, but so enraptured by his inner world that nothing he made could obtain relevance on its own; instead made famous by his antics. Also doesn't mean all schizophrenics have a high IQ. The two aren't always correlated.

i have been diagnosed with schizophrenia from 1996 and i have beaten many grandmasters and had an online rating of 2350 standard not blitz on the if anything underrated icc server(Internet Chess Club), i have also done a physics degree and got a 2.1(hons), and got a degree equivalent in computer programming, i have run a web design business for 3 years as a sole trader, making a profit