Everyone is so cynical in this thread. It might not be conlcusisve evidence of a direct connection between the two but it does look like an interesting observation.
this post was submitted on 09 May 2026
228 points (96.0% liked)
science
26956 readers
427 users here now
A community to post scientific articles, news, and civil discussion.
dart board;; science bs
rule #1: be kind
founded 2 years ago
MODERATORS
Suppose my reaction to that is "Really? No known cases of schizophrenia among those blind since birth? They should study that."
Maybe they do but they just don't know the voices they hear are in their head
Meh...
Schizophrenia is really fucking hard to diagnose, someone whose never been able to see, can't experience visual hallucinations, they just can't. And that's the main symptom, the one that people not only experience but can usually eventually figure out aren't real.
They can experience auditory hallucinations, but are likely to have not only an inner monologue, but a richer one with more variation due to no vision. Creating narratives even subconsciously would help navigate figuratively and literally. With relaying on hearing so much, "false positives" would also likely be common, a study on how often blind people think they may have heard something may shed light. "Did someone say something" moments may mask auditory hallucinations.
It's entirely possible there's blind schizophrenics, and they're either misdiagnosed or undiagnosed.
One thing that is weird, people born deaf also can't experience auditory hallucinations, so instead they experience "floating hands" visual hallucinations that angrily sign at them.
So I'd be curious into research if schizophrenia in someone whose never experienced sight is exhibited in a radically different way. The symptoms are still just symptoms, they're not what's causing the issue. So it would make sense when such fundamental systems as vision and hearing are interrupted, symptoms may manifest in radically different ways, or even unnoticeable ways
I work with a deaf schizophrenic person and they talk (write, sign) about their "mind being quiet" or being "way out of my mind". When clearly experiencing symptoms they'll often look, sign, yell or kick at a specific area but can't really detail what exactly's happening in those moments.
In my experience the behavioural elements of schizophrenia would be hard to miss, i doubt visual vs non-visual hallucinations would change that.
My understanding is it can be hard to narrow down schizophrenia vs other diagnoses, but it's usually obvious that something is going on. I'd think if people were looking for blind schizophrenia cases they'd at least have a pool of likely candidates to look into.
I'm instantly skeptical of "no blind schizophrenics" but it's just gut. I can't think of any explanation.
someone whose never been able to see, can’t experience visual hallucinations, they just can’t.
That would be really hard to assess. Hallucinations happen in the brain, so even if the eyes were nonfunctional or literally absent, that chunk (occipital lobe) of the brain isn't necessarily just turned off, so it's not a huge leap to conclude that that chunk could still crank out the sensation of sight in some way during a hallucination.
But without the context of actual sight, that sensation wouldn't carry much meaning, and would probably be really hard for that person to describe.
Interesting thought!
that chunk (occipital lobe) of the brain isn’t necessarily just turned off,
No it's literally just people blind due to issues with the brain not just the eyes, it says that in the article.
But without ever having visual input, it can't produce a visual hallucination. The brain wouldn't have any frame of reference and it's not like a "dark room" where you're still trying to see and experience a blackness, with that kind of blindness from birth there is just nothing, not the absence of visual input, the complete ignorance that a visual field exists. That's why some blind people still "stare ahead" they were likely able to see at some point or have some functional vision. 100% blind from birth and the eyes move independently and randomly. That person never learned to coordinate their eyeballs as an infant, they've never had any feedback.
(Pre-emptive edit: do not assume anything about someone else's ability, crazy fucking shit exists. Like, "blindsight" is real. Super rare, but sometimes someone just doesn't conciously have vision, but if you chuck a wrench at their head instinct takes over and they duck. That does not mean someone is "faking it")
The brain isn't just going to let the occipital lobe gather dust, it's going to repurpose it to handle something else like how a split brain patient who was young enough for the procedure to retain the brain plasticity necessary to form a second language center on the other hemisphere.
If anything that is where protection is coming from, the brain has a pretty big chunk to fill in defecinicies elsewhere.
I understand the claim, what I'm saying is that it would be difficult to confirm. Not having a visual reference would mean their experience of visual input would be distinct from ours, but concluding that it doesn't happen at all is a stretch.
As a hypothesis, my guess would be their experience of visual sensation of a hallucination would come as raw input - flashes of light or something.
The problem would come with asking that person to tell you if they see flashes of light if they've never experienced real light. How their brain re-wired that chunk is a complete mystery to an outside observer. If visual processing is reassigned, it would be to something completely unrelated: like, light perception could now be tied to decision making, with good ideas feeling brighter vs risky ideas feeling dark. Or vice versa.
But to them, that processing of visual feedback isn't a visual experience, so asking if they've seen flashes of light would be like me asking you if you've ever tasted an ethical dilemma or some other concept: the question wouldn't make sense, and we would have no way to make it make sense without knowing ahead of time that it's tied to decision making. And if it was, a visual hallucination could come as making them feel erroneously confident about a risky behavior simply because the visual cortex is giving the perception of brightness to literally every thought.
So again, that would be really hard, if not impossible to assess, and claims to have done so would need a lot of evidence to back it up.
Not having a visual reference would mean their experience of visual input would be distinct from ours, but concluding that it doesn’t happen at all is a stretch.
It literally would...
Because of the type of blindness they're talking about...
You don't understand anything else, because you're still trying to talk about any sort of visual impairment
I'm sorry I can not explain this in a way you can understand, but I've also lost all motivation to try with anything else at this point.
You'll need to find someone else
It literally would... Because of the type of blindness they're talking about...
An article talking about something doesn't make it true. "Because of the type of blindness we're talking about" doesn't explain anything, and that kind of 'trust me bro' blanket pseudo-rationalization doesn't scratch the surface of how we'd be able to understand the perceptions of someone who's preceptive foundation is fundamentally different from our own.
But keep telling me how that doesn't mesh with the article.
My understanding was hallucinations didn’t specifically have to be visual, aural hallucinations were are sufficient to check the hallucinations box, is this incorrect?
aural hallucinations were are sufficient to check the hallucinations box, is this incorrect?
Auditory hallucinations but yeah....
What I said was that "did someone say something" false positives that you heard something are easily handwaved away, pretty normal.
But visual hallucinations are often what makes a schizophrenic realize that they're experiencing hallucinations. Because a visual hallucinations can't interact with reality.
If a blind person hears "fuck you Bob, step in the street"...
Bob can't be 100% sure there's not someone fucking with them.
That could be all the "protection" is, just having the benefit of the doubt. They could be experiencing shit, but just fucking dealing with it.
That is correct, also not all types of schizophrenia have hallucinations as symptom at all. A diagnosis of paranoid schizophrenia does not require hallucinations among the symptoms.
Visual hallucinations is not the main symptom of schizophrenia though. You have all sorts of positive and negative symptoms, plus cognitive. Most patients do not "see" things that aren't there, in the way people commonly believe.
You have all sorts of positive and negative symptoms,
Yes, all the wonderful positives of checks notes schizophrenia...
That's not at all what the term means. In psychology, "positive symptoms" refers to symptoms that are added to typical functions, such as experiencing hallucinations. Likewise, "negative symptoms" are symptoms that take away from it, such as having reduced emotions.
I'm skeptical, yet very interested.
correlation is not causation
No one claimed it is
No but to me it implies the occipital lobe, specifically the visual cortex, is somehow related to the development of schizophrenia.
I read in an eeg-textbook, years ago, that the reference-voltage for normal EEG's was 50-microvolts, but in a schizophrenic's psychotic-fugue/episode, it can be required to be 250-microvolts.
It may simply be that with much of the brain understimulated, the threshold-for-paralyzed-in-dysfunction isn't ever crossed.
Sorta like those drag-racing cars, whose engines explode if run for 1-single-second more than the race they're built-for..
Stay below the energization-threshold ( blind-since-birth ) & then no problem.
Energize everything, & then the over-energized-to-being-broken threshold gets crossed.
It may have nothing to do with the visual-cortex itself, iow.. only with overall-brain-energization, that's creating this difference..
Also, a researcher named Thompson ( whose papers have been disappeared from the internet, now ) did a periodic-brain-scans-of-children study, where he showed that child-onset-schiphrenia involves the loss of 20% of the upper-forebrain, in a particular region, & the scans mapped where brain was being lost, in different areas..
The 10%-total-brain-reduction that has been known-about since the 1920's isn't even loss it is specific-areas which get corroded-down.
Having an already-full-cup, then reducing-the-size-of-the-cup, may be why it's a problem, & having a not-full-cup, with brain-capacity that's being underused, may allow adapting to it without dysfunction.
_ /\ _
The most rigorous evidence comes from a 2018 whole-population study tracking nearly half a million children born in Western Australia between 1980 and 2001. Of those, 1,870 developed schizophrenia, but not one of the 66 children with cortical blindness did.
1,870 / 500,000 = 0.374% of people in the general population
0.374% * 66 = 0.25
Not particularly rigorous.
This is because, as a simple calculation demonstrates, a case of congenital blindness and schizophrenia would be extremely rare even if there was no protective effect of blindness: if schizophrenia occurs at a rate of 0.72% in the population (McGrath et al., 2008) and congenital blindness occurs at an estimated rate of 0.03% in people born in the 1970s and 1980s (based on Robinson et al., 1987), then the joint probability of a person having both conditions, if the two are independent, would be 0.0002% or 2 out of every 1 million people. Although this is a low prevalence rate, it is equal to or higher than the rates for several other well-known conditions (e.g., Creutzfeldt-Jakob disease, hereditary spastic paraplegia, Hermansky-Pudlak Syndrome). Based on this estimated prevalence rate, in the United States alone (with a population of 311, 591, 917, as of July 2011, according the US census), there should be approximately 620 congenitally blind people with schizophrenia. When cases of blindness with an onset in the first year of life (i.e., early blindness) are taken into account, the percentage would be larger. Therefore, it is remarkable that in over 60 years, and with several investigations [including several before DSM-III (1980) when criteria for schizophrenia were broader than at present], not a single case of a C/E blind schizophrenia patient has been reported.
https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2013.00157/full
Not particularly rigorous.
Nah, because of the numbers, only 1k people is enough of a sample size for every human.
It's exponital increase, not a flat increase...
1,000 isn't even close to the minimum, it's just a nice round number and it's not difficult to reach.
It's easily provable by finding any "sample size calculator" and trying to get it to tell you to go over that mark.
The standard 5% confidence interval is really what's at play. But sample size is day 1 stuff, trying to explain it isn't going to work just play with the calculators and see it's impossible.
What about those who are blinded later? Are blindfolds a cure for schizophrenia?
The answer's in the article...
view more: next ›