People who are blind from birth never develop schizophrenia

(theconversation.com)

41 points | by debo_ a day ago ago

35 comments

  • SideQuark 18 hours ago ago

    > 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.

    1870/500,000 * 66 = 0.247

    Not a single blind child getting it is the most likely outcome, and this is called "the most rigorous evidence"?

    It didn't protect rats in a study https://www.sciencedirect.com/science/article/abs/pii/S09209...

    There sure is a lot of reported cases of all sorts of blindness with schizophrenia, constantly shrinking the pool of types of the two, making this conjecture constantly shrinking https://pmc.ncbi.nlm.nih.gov/articles/PMC4246684/

    It also seems the Australia study does not quite say what the article claims it does - a follow-up study: https://jmsgr.tamhsc.edu/the-lack-of-comorbidity-between-ear...

    Too bad this article simply doesn't mention all this. Of course the article will get less clicks with a less wild title.

    • 2 hours ago ago
      [deleted]
    • protimewaster 12 hours ago ago

      Doesn't the article address some of that in the next paragraph, which includes a link to a study from 2013?

      > That sample of blind children is small, but the pattern holds across more than 70 years of evidence: not a single congenitally blind person with schizophrenia has ever been reported. The protection seems to be specific to cortical blindness, which is caused by damage to the brain’s visual cortex.

      I believe that also addresses the discrepancy between the 2014 study you linked and the article. That 2014 study you linked is noting that it does happen with other kinds of blindness. I haven't been through the whole 2014 study (or the 2013 one, for that matter), but it does say

      > As the case-reports presented in this section show, only congenital/early cortical blindness—the type of blindness that occurs when bilateral lesions of the occipital cortex deprive the individual from vision (Cummings and Trimble, 2002, p. 110)—seems to confer protective effects.

      Isn't that saying the same thing the article does. What am I missing?

      • SideQuark 7 hours ago ago

        > but the pattern holds across more than 70 years of evidence

        No, those are also stupidly small samples. Look at the papers I listed.

        > That 2014 study you linked is noting that it does happen with other kinds of blindness

        Yes, from 1950 till 2014, as more and more kinds of blindness were found with schizophrenia, the type of blindness has been dwindling to smaller and smaller classes, ensuring there is not enough predictive power in the claims. Again, look at the papers I listed. ALL of this is covered.

        > Isn't that saying the same thing the article does.

        The article says lots of nonsense, like the most likely outcome of data is somehow the best evidence for an unproven claim. It implies the Australia study says a thing it DOES NOT SAY. Is this not enough bad reporting to question the accuracy of the article?

        > What am I missing?

        Simply look at the papers I posted. They are right there for you to read. The article is click bait trying to claim there is some surprising scientific claim that HAS NO SCIENTIFIC PROOF.

  • altairprime a day ago ago

    Huh. I wonder if that means my inability to visualize mentally means I’m partly/fully defended against it? That would explain a subgroup prevalence!

    • eadwu 35 minutes ago ago

      No, you can definitely still be schizophrenic.

      Consider the combination of senile + mirages.

    • 21 hours ago ago
      [deleted]
    • 2ndorderthought 20 hours ago ago

      Probably not you are likely an afantist though

      • pseudohadamard 9 hours ago ago

        Well the voices have definitely told me my aphantasia is keeping me safe.

  • a day ago ago
    [deleted]
  • hyperhello a day ago ago

    Off topic, but do deaf people ever hear voices?

    • theturtletalks a day ago ago

      I’ve heard they actually see people signing at them. Also, in India, the voices are actually nice and encouraging I’ve heard.

      • 2ndorderthought 21 hours ago ago

        Contrary to popular belief not all delusions and hallucinations are horrifying. Similarly, not all of them compel people to do bad things. There are cases of schizophrenics who had voices and hallucinations telling them to be good to people and go out of their way to help strangers. There's definitely all sorts though it's not like one or the other or that a person only has one type.

        • spoiler 19 hours ago ago

          If I'm very tired (after I had insomnia for two or so days) I have mild hallucinations, and they're pretty boring/benign. But mine are more auditory than visual.

          This isn't unusual when people are sleep deprived though. I think lots of people just don't realise they are hallucinating in that state

      • solumunus a day ago ago

        > Also, in India, the voices are actually nice and encouraging I’ve heard.

        And you’re not as skeptical of this claim?

        • wahern 15 hours ago ago

          There's been several studies. The same phenomenon happens in the US among a subset of people who frame the voices in terms of older cultural narratives like, e.g., hearing the dead (i.e. traditional Western spiritualism), or with immigrants who came of age overseas. The critical elements seem to be 1) how the culture primes the person to frame the hallucinations, and 2) how family, friends, and other community members receive the claims. If both are positive or at least benign, it's less likely for the symptoms to become debilitating. Stress has a well known and very strong effect on progression of the disease. If you have angry, scary, violent voices, or when the community around you reaffirms the negativity and pathological nature of the voices, your stress levels go up tremendously.

          The priming effect is huge, I think. American culture loves conspiracy theories, and conspiracy figures prominently in the experiences of American sufferers. Likewise for tropes like nefarious government surveillance, not to mention how both are infused with literal and tacit threats of extreme violence, or demands of violent responses. That's just not true to the same degree, if at all, most other places, with notable exceptions being other Anglo countries, which share similar cultural histories, not to mention sharing to a much greater degree Hollywood media which express and popularize these kinds of stories.

        • hyperhello a day ago ago

          I’m not, actually. I think we all have inner voices if we listen, and it’s possible that different societies have different characteristics. One of them could be whether the environment is on the individual’s side or not. A more compatible inner voice could do better in either situation.

          • 4gotunameagain a day ago ago

            And the environment in India is on the individual's side ? Where people starve in broad daylight and corpses float on rivers ?

            • tsol 19 hours ago ago

              Probably has more to do with how they regard hallucinations. In some cultures they're regarded as possibly mystical and a good thing, in other cultures they're regarded as strictly a sign of a malfunctioning brain which is of course bad. Even a corpse can create different feelings based on context and beliefs-- ie a corpse at a funeral is a somber memorial, a corpse lying in the street is sad and worrying.

            • hyperhello a day ago ago

              I didn’t say inner voices are scientifically correct. I think they’re an adaptation. Maybe if India had more functioning depressives it wouldn’t be in that situation, who knows?

            • hgoel 17 hours ago ago

              And you’re not as skeptical of this claim?

        • DANmode 18 hours ago ago

          Why? It wouldn’t surprise me if people felt safer around Others in general there (aside from contentedness).

          https://pubmed.ncbi.nlm.nih.gov/26349837/

        • anon291 18 hours ago ago

          I'm not because my schizophrenic uncle moved from India to America and went psycho, moved back and was normal again.

  • shirro 19 hours ago ago

    My understanding is that auditory hallucinations are more common in schizophrenia which makes this more of a WTF.

    Aphantasiac here so this raises an obvious question. Cursory search suggests visual hallucinations due to drugs or schizophrenia are reported. Conscious and involuntary visualisation seem to be somewhat independent.

    • finghin 11 hours ago ago

      As I said in another thread, visual hallucinations (without intoxication) are certainly a thing, but they are quite rarely associated with schizophrenia. There is far, far more to the condition than hallucinations or even psychosis more generally, but hallucinations are most commonly auditory

  • lurquer a day ago ago

    “…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.”

    Using this data, one would expect to see only 0.25 cases in those 66 blind kids.

    Stated differently, there is around a 78% chance of having 0 cases in those 66 by random chance alone.

    Dumb.

    • xdavidliu 21 hours ago ago

      this is the type of math they should be teaching in high school, not trigonometry and calculus (which should be electives)

      • tim333 2 hours ago ago

        Calculating 1870/500000*66 is kind of basic arithmetic that is covered in high school. They could maybe have some classes in debunking bs media claims which are quite plentiful these days?

    • 2ndorderthought 21 hours ago ago

      I got all interested and you are right. The math isn't mathing. For social science though this is what they have to do to fund more research. At least there isn't a greater incidence? ... ? ... ?

    • yladiz a day ago ago

      Can you explain how you got that number from the quote? I don’t follow.

      • bhattid a day ago ago

        Not the original commenter, but the math is (making some implicit, but arguably reasonable assumptions):

        Probability that someone in the population has schizophrenia = (1870/500000) = 0.00374

        Probability that someone does NOT have schizophrenia = (1 - 0.00374)

        Then if we assume that blind people have the same rate of schizophrenia as the population, Probability that 66 blind people ALL don't have schizophrenia = (1 - 0.00374)^66 = 0.78

        • lurquer 21 hours ago ago

          The sad thing is that IF — by chance — one of those 66 had schizophrenia, the headline would undoubtedly read “Blind children are FOUR TIMES more likely to develop Schizophrenia!”

      • wizzwizz4 a day ago ago

        1870/500000*66 = 0.24684. However, it's "nearly half a million", so let's call it 30000 as a conservative estimate: that's still 0.4114 children in expectance, which isn't very many.

    • solumunus a day ago ago

      “That sample of blind children is small, but the pattern holds across more than 70 years of evidence: not a single congenitally blind person with schizophrenia has ever been reported.”

      • debo_ 20 hours ago ago

        It's ok, people in the life sciences are very accustomed to people from other fields assuming they are stupid.