No person who was born blind has ever been diagnosed with schizophrenia

If you’re wondering about how common this should be:<p><i>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 0.02% or 2 out of every 10,000. Although this is a low prevalence rate, it is higher than the rates for childhood-onset schizophrenia (Remschmidt and Theisen, 2005), and many other well-known medical conditions (e.g., Hodgkin&#x27;s lymphoma, Prader Willi syndrome, Rett&#x27;s Syndome). 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.</i> <a href="https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC3615184&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC3615184&#x2F;</a><p>That does do rule out misdiagnosis etc, but it does seem to support a correlation.

Very interesting. I wonder if there&#x27;s a link between melatonin production in the pineal gland (affected by visual perceptions of light) and endogenous DMT, also suspected of being produced in the pineal (see Rick Strassman&#x27;s work)<p>For a long time endogenous DMT, or some other endogenous psychoactive compound, was suspected of being a cause of schizophrenia. I think it&#x27;s largely discredited by now anyway.

I think the vast majority of schizophrenics have relatively mild symptoms (just as most diseases have more sufferers of a mild version vs. more severe version) and their diagnosis is made primarily because they have a disease that makes it hard for them to be 100% self sufficient, and there needs to be a paper trail in place that documents this.<p>Although the majority of blind people have essentially 100% self sufficiency (maybe with some occasional help from family&#x2F;friends on some edge cases) I suspect it is relatively easy for a congenitally blind person to get financial and other assistance in the US, since as a society we are fairly supportive of people with obvious congenital disabilities. I could therefore imagine that if there was mild schizophrenia in a congenitally blind person, there&#x27;d be far less incentive for the affected person or their family to establish a formal diagnosis to this effect.<p>I wonder if this could be a partial explanation for this surprising statistic (and the lack of evidence for severe schizophrenia could maybe just be due to inadequate sample sizes in the OP study to detect this smaller set of people.)

Maybe the visual center has more trust over auditory or other parts of the brain? For example an auditory hallucination is easily discounted, but if most people witnessed a visual hallucination, they&#x27;d question their own sanity because that signal is so trustworthy? There&#x27;s many other explanations just a random thought.

Isn&#x27;t it that when you combine two extremely low prevalence phenomenons together, you can&#x27;t really make any accurate predictions because the numbers are so low that the error margin is too high? I might be wrong, but I seem to remember something to that effect. Could it be what&#x27;s at play here?

That paper suffers from a small number problem.<p>With simple probability, using their 0.4%, it means that you would expect 0.26 blind child out of 66 to have schizophrenia. So that they see 0 is perfectly reasonable. For the other psychotic illness, that probability is 1.5%. So, out of 66 you would have expected 0.99. Maybe that kid is the lot and will develop apparent symptoms of psychosis in the next few years...<p>In general, an epidemiology study without statistic means that they try to find something but they didn&#x27;t and couldn&#x27;t explain why.<p>Now, common epidemiology statistic are going to use a 5% alpha error and a 95% confidence. So, if they were to repeat that experiment a 100 times, 95 times you would observe a value close to the mean. The probability numbers given are maximum, and I would guess that the minimum is zero. So 95% of the time, you would have a value much lower, and closer to zero individuals out 66 for psychosis.

Even if there&#x27;s some sort of genetic or environmental barrier, you would think that it would happen at least once as a misdiagnosis.

From my admittedly completely uninformed position, this looks so much like academics searching for some profound insight that will win a Nobel prize (or perhaps just guarantee a tasty stream of research grants) when in reality the truth could be much simpler. Let&#x27;s look at an example of a group that suffers disproportionately:<p>&#x27;The high level of schizophrenia in black Caribbeans living in the UK probably reflects the interaction of multiple risk factors, many of which cluster in the black Caribbean community in the UK. Particularly significant factors appear to be the combination of isolation and exclusion, both within society (living in areas of low ethnic density and reduced participation in society) and within the family (family break-up and paternal separation). These factors seem to be more powerful than socioeconomic disadvantage, which is more likely to be a consequence than causal. Racism itself may contribute to social exclusion, increasing the vulnerability to schizophrenia. Biological or genetic susceptibility do not appear to explain high rates of schizophrenia in black Caribbeans. More research is needed about the role of cannabis, particularly in its more potent forms, and whether this contributes to the excess of schizophrenia in black Caribbeans.&#x27;<p>Perhaps it&#x27;s as simple as: people that are born blind are to some extent insulated from risk factors that are conducive of schizophrenia.<p><a href="https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC2418996&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC2418996&#x2F;</a> (just the first article I could pull up on a phenomenon I was aware of)

I wonder if this points to the problems in the concept of this diagnosis.<p>It has been seriously questioned since World War II as to whether schizophrenia is even a disease.<p>The questioners being mostly from the psychoanalytic school (some psychiatrists), all forgotten, may have something to do with it.<p>In my family more than half of one side of my immediate parent-generation family members have been diagnosed with the disease. Most of them get by with little to no drugs.<p>All of them were diagnosed in connection with divorce proceedings.<p>(We had a misunderstanding. You must be hearing voices.)<p>I could not help but believe, admittedly biased, that this is &quot;health&quot; as a locus of power, blame, and control.<p>In higher education I had close blind friends who achieved high marks and went on to work in Fortune 500 companies, at a level not unlike people I knew before they got hit with a diagnosis. Did they have disagreements with loved ones? Sure. If they had found themselves in a bitter marriage and divorce, would something they said be weaponized into a diagnosis of mental illness? Maybe. At the rate of the general population? Maybe. I don&#x27;t know.<p>I am not criticizing, accosting, or accusing anybody of anything. Just asking some questions.

So what does that imply? That visual sensory input might trigger schizophrenia? But that would imply that blind people have diminished sensory input. I just don&#x27;t buy that.<p>They have a lot of sensory input, perhaps as much as seeing people. It&#x27;s just delivered differently. Try an isolation tank. I can totally imagine someone going crazy in one of those.<p>The original title was even more click-bait. I&#x27;m glad it was changed before posted here.

What if we could “reboot” a schizophrenic brain through some sort of sensory deprivation?

Does aphantasia have any impact?

Schizophrenia is a grouping of symptoms that are generalized to an inability for a person to smoothly track reality. For example, when a person without schizophrenia attempts to track the trajectory of an object, the eyeballs follow a smooth path. When a person with schizophrenia attempts the same, the eyeballs do not follow a smooth path, with the focal point moving chaotically off center from the target. A part of the diagnostic criteria for schizophrenia is testing whether or not the eye can smoothly track the movement of an object. This would likely be why it is difficult to diagnose someone that was born blind.<p><a href="https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC3212396&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.ncbi.nlm.nih.gov&#x2F;pmc&#x2F;articles&#x2F;PMC3212396&#x2F;</a>

Just speculating, but being born blind has (in recent history at least) led to a quite sheltered and protected life. For those cases caused by &#x27;chemical imbalances&#x27; (genetic factors), &#x27;sheltering&#x27; would not help. For cases that occur in response to the external world (environmental factors), the &#x27;sheltering&#x27; might have a shielding effect.<p>If so, then the not-blind vulnerable should avoid stress.

Interesting. Can it also have something to do with an extremely small sample size? These are both rare conditions so intersection might be even rarer.

Many antipsychotics are also used as anti-seizure medicines. Seizures are often induced by visual stimuli. The brain is weird.

Hearing voices in your head without having sight to confirm if anyone&#x27;s actually there or not sounds actually terrifying.

I would like to hear more about that, about other mental illnesses, depression etc... Does being blind also affect these?

It seems intuitive to me that visual centers of the brain don&#x27;t develop properly in the absence of visual stimulation. Has anybody done fMRIs to compare congenitally blind people with those who became blind later in life? Also it begs the question: which blind person with schizophrenia became blind at the youngest age?

What&#x27;s the chance that any two low probability unrelated conditions happen to have an empty overlap at random?

Marshall Mcluhan hypothesized that schizophrenia may be a consequence of literacy

It may only be that what we consider to be schizophrenia in a physiologic sense presents entirely different in the blind and is unrecognizable despite being present.

Correlation doesn&#x27;t mean causation.

This reminds me of a Sandra bullock movie

Not sure if this will get buried, but I have an anecdote to support the visual link, which may also help anyone dealing with psychic issues.<p>I was 23, living abroad, feeling totally isolated.<p>One day, I smoked weed which led to an &quot;episode&quot; I guess you could say -- quite literally I was hallucinating that I was in a hospital, while i was in my room.<p>What happened next was weird. I felt extremely depersonalized for weeks and months after, concurrently I developed a swirling blind spot in my right eye.<p>A distortion, so to speak.<p>I saw neurologists and was diagnosed as having an &quot;ocular migraine&quot; however I never had a headache so this didn&#x27;t add up.<p>Looking back, I believe I was on the brink of becoming schizophrenic - and would have unless what happened next did.<p>So this next part is slightly controversial -- but hear me out<p>Through the several months that would follow I would discover and get obsessed with &quot;RSD&quot; -- a controversial company that teaches guys how to pick up girls.<p>On the surface, it sounds crass and not politically correct, but if you watch their videos &quot;get you in the door&quot; with &quot;game&quot;, and teach you topics of incredible value, like &quot;growth mindset&quot;, &quot;the power of now&quot; &#x2F; meditation and believing in abundance.<p>Now WTF does this have to do with the topic at hand?<p>Well, being receptive to these new ideas and absorbing them completely changed my world view.<p>I grew up in an extremely liberal household, and did feel any agency to affect the world around me. Fixed mind set.<p>What these guys gave me was empowerment, agency, a more conservative mindset under which the world &quot;made sense&quot; - there was now a framework for reality, rather than chaos.<p>Subsequently, I was able to learn programming from scratch, start a business, go on to make 6 figures less than a year later.<p>Somewhere along the line the distortion and negative feeling were entirely replaced. I couldn&#x27;t tell you when.<p>tl;dr: I was close to schizophrenia which manifested itself in visual symptoms, overcame with a mindset change

Just queried my health system database and this statement as it pertains to congenital cortical blindness is factually incorrect.

I don&#x27;t think schizophrenia has any dependence on visual input at all. This is just a probability problem, since the combined probability of both occurring is very small, as the separate probabilities are already small; Anyone that has a brain can have the disease, blind or not; The disease itself is very little understood. For example, when I was a child I had visions and heard voices. I would go to sleep and then, in the middle of the night I would wake up and start seeing things around me, hundreds of voices talking, light beings, etc. Some would call me a schizophrenic, some a medium. I could be both, could be neither;