Psycho-Babble Medication Thread 1108443

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No person born blind has ever been Schizophrenic:

Posted by PeterMartin on February 12, 2020, at 8:06:02

New article from today (Feb 11, 2020): People Born Blind Are Mysteriously Protected From Schizophrenia

Fascinating.

https://www.vice.com/en_us/article/939qbz/people-born-blind-are-mysteriously-protected-from-schizophrenia

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t was something Tom Pollak had heard whispers aboutan odd factoid, referred to now and again, usually with bewilderment: No person who was born blind has ever been diagnosed with schizophrenia.

Over the past 60-some years, scientists around the world have been writing about this mystery. They've analyzed past studies, combed the wards of psychiatric hospitals, and looked through agencies that treat blind people, trying to find a case.

As time goes on, larger data sets have emerged: In 2018, a study led by a researcher named Vera Morgan at the University of Western Australia looked at nearly half a million children born between 1980 and 2001 and strengthened this negative association. Pollak, a psychiatrist and researcher at King's College London, remembered checking in the mental health facility where he works after learning about it; he too was unable to find a single patient with congenital blindness who had schizophrenia.


These findings suggest that something about congenital blindness may protect a person from schizophrenia. This is especially surprising, since congenital blindness often results from infections, brain trauma, or genetic mutationall factors that are independently associated with greater risk of psychotic disorders.

More strangely, vision loss at other periods of life is associated with higher risks of schizophrenia and psychotic symptoms. Even in healthy people, blocking vision for just a few days can bring about hallucinations. And the connections between vision abnormalities and schizophrenia have become more deeply established in recent yearsvisual abnormalities are being found before a person has any psychotic symptoms, sometimes predicting who will develop schizophrenia.

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But the whispered-about fact persists: Being born blind, and perhaps specific types of congenital blindness, shield from the very disorders vision loss can encourage later in life. A myriad of theories exist as to whyfrom the blind brain's neuroplasticity to how vision plays an important role in building our model of the world (and what happens when that process goes wrong). Select researchers believe that the ties between vision and psychotic symptoms indicate there's something new to learn here. Could it be that within this narrowly-defined phenomenon there are clues for what causes schizophrenia, how to predict who will develop it, and potentially how to treat it?

In 2004, 13 healthy people were blindfolded for 96 hours, and 10 of them reported having visual hallucinations between their first and second day in the dark.

One subject, a 29-year-old woman, saw a green face with big eyes when she was standing in front of where she knew there was a mirrorthough she couldnt see it. Another 24-year-old man, by the end of the second day, was having difficulty walking because of all the hallucinations that appeared to be in his way. He reported seeing "mounds of pebbles, or small stones...and between them was running a small stream of water." By the end of the study, he reported seeing "ornate buildings of white-green marble" and "cartoon-like figures."

We've known for a long time about the link between vision loss and hallucination. Charles Bonnet syndrome, first described in 1760, is a disorder in which people lose their vision and then start to experience hallucinations. These kinds of mental conjurings don't necessarily come with mental illness, though people with schizophrenia have been regularly shown to also have issues with their sight.

Having unusual eye movements, problems with the retinas, unusual blink rates, and other visual aberrations makes it more likely for a person to be diagnosed with schizophrenia. One study found that those vision problems start before a person has their first psychotic episodes, not after.

Yet this association falls away among people born without sight. Pollak and Phil Corlett, an associate professor of psychiatry and psychology at Yale University, have a theory about whywhich they published late last year in the journal Schizophrenia Bulletin. It's rooted in the hypothesis that one of our brain's most important jobs is to make predictions about the world.

Watch more from VICE:


This view of the brain argues that rather than perceiving the world around us in real time, our brains create a model of whats out there, predict and simulate what we experience, and then compare our predictions to whats actually happeningusing any errors to update or change the model in our minds. The accuracy of your past predictions are crucial for the accuracy of your overall modelit's what you're comparing new inputs to, and how you're making any adjustments.

This is where vision comes in. Vision gives us a lot of information about the world around us, and is an important sense that helps link together other sensory cues, like sound and touch, Pollak said. If the way a person sees the world is off, it can make it harder to predict, correct errors, and build a model of the world that makes sense. And when people have problems with their vision, the brain has to make more predictions to explain them. On the other hand, if you couldnt see anything, you wouldnt build up those false representations of the world around youwhich could lead to problems in thinking later on.


This might help researchers explain all those issues in vision and sensory processing early in life seen in people with schizophrenia. In a 2006 study by Elaine Walker at Emory University, she analyzed home movies of people diagnosed with schizophrenia when they were children. A lot of the children were more clumsy in the videos, like dropping a ball more frequently during catch, stumbling more often, or tilting to the left side. It suggests there's some sort of disconnect with the way theyre sensing and interacting with the world. When children of mothers who have schizophrenia show visual dysfunction when theyre young, it can predict if they develop schizophrenia when theyre older. Children who end up with schizophrenia, both with and without a family history, have more problems with their eyes compared to children who develop non-psychotic diseases or other mental illnesses.

A person who was born blind doesn't have the visual inputs to help shape their model of the world. They have to build it with their other sensesa model of the world that Pollak and Corlett argue could be more stable.

The idea were trying to get at is, there must be something different in the representation and the stability of the internal world in congenitally blind people, Pollak said. And that stability, in a way, is keeping itself protective against the kind of mistakes and false inferences that you get in schizophrenia and psychotic disorders.

The hallucinations, delusions, and bizarre behavior in people with schizophrenia are well known. But Steve Silverstein, a psychiatrist at the University of Rochester, said that he and others view those symptoms as side effects, not the cause of the disease. Actually, schizophrenia could be more rooted in cognitive deficitsdisturbances in perception, attention, memory, language, or learning.

Around 2010, Silverstein read Blind Visiona book by scientists Zaira Cattaneo and Tomaso Vecchi, on the cognitive abilities and experiences of blind people. I was struck by how many of the compensations that the brain seems to make, or the skills that blind people develop, seem to be the exact opposite of what you find in schizophrenia, he said.

Silverstein doesnt disagree with Pollak and Corletts predictive brain theory, but thinks that the answer may be more far-reaching: that prediction is just one way a congenitally blind person's brain has advantages over a schizophrenic brain. He thinks that being blind strengthens the brain in various waysand in the very same ways that it is weakened when someone has schizophrenia.

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To take one example, theres something called selective attention when it comes to listening, which is the ability to stay attentive to one source of auditory informationsay, when youre at a party and listening to one person without letting the sounds from the rest of the room distract you. In a lab setting, researchers test selective attention by playing one noise into your left ear and a different one into your right, asking you to pay attention to one and not the other.


People with schizophrenia have been shown to have problems with selective attention, Silverstein said, and meanwhile people who were born blind are better at this task than sighted people. When compared to sighted people, congenitally blind people are also better at hearing different pitches, telling pitches apart, and telling where sounds come from. People with schizophrenia are the opposite: They usually have difficulty with listening accuracy, and process speech abnormally. Not being able to properly figure out where sounds are coming from could lead to someone thinking that their own voice is coming from somewhere else, and contribute to delusional thinking.

It's a compelling list that goes on and on: Blind people are better than sighted ones on reaction time to both sound and touch; schizophrenia patients show deficits in these areas. Blind people have better working memories, and people with schizophrenia can have impairments in memory. Congenitally blind people are also impervious to the rubber hand illusion, when a person feels like an inanimate object is part of their own body (the experiment is typically done using a rubber hand). It could mean that blind people have more stability when it comes to their bodily representation.


I would say there are probably about 20 ways that people who are born blind are better, on average, than people in the general population, Silverstein said. And its in those same areas where people with schizophrenia tend to have more cognitive problems. (He's even made a chart, published in one of his papers.)

"If you're born blind, your brain basically from an early age takes over the visual part of the brain to do other things," Silverstein said. "And that's thought to be the reason why some of these auditory, attentional, and body-representation skills are a little more developed in people who were born blind than other people." Another result of blindness is that brain regions are talking to each other more, in ways they dont in sighted peoplesome brain-imaging studies have seen that. People with schizophrenia, meanwhile, tend to have many fewer of these connections.

A concrete explanation for why congenital blindness protects from schizophrenia is still up for grabswhether the protection comes from predicting the world, having a more connected brain, or relying on other senses.

Theres a lot that needs to be fleshed out. For example, there is more than one kind of congenital blindness. Cortical blindness is caused by an issue in the part of the brain that processes vision, whereas peripheral blindness is a problem in the eyes insteadbut the visual part of the brain is okay. While there are still no reported cases of people with congenital cortical blindness, there might be a few people who were born blind with peripheral blindness who did develop schizophrenia. (Some of the cases are several decades old, or the person has other serious diseases, so saying for sure is tough.)

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Congenital blindness doesnt seem to protect against any other mental illness, so its not a safeguard overall. Congenitally blind people have been reported to have had eating disorders and arachnophobiaa person can have those disorders without ever having seen their bodies or a spider). And if a person is born both deaf and blind, it doesnt seem to offer protection eitherthat comes with higher risks for psychosis.

Theres a disease called Usher syndrome, in which people are born deaf and lose their vision early in childhood; its been associated with schizophrenia and psychosis. Silverstein said that its unclear why adding deafness to the mix removes the protection that blindness seems to offer. One possibility is that blindness by itself presents a surmountable challenge to cope with the environment and thereby fosters compensatory sensory, perceptual, and cognitive changes that lead to a surprisingly high level of functioning, Silverstain wrote in a 2013 paper. Deafblindness, on the other hand, may so seriously restrict the opportunity for environmental interaction that it also stunts the development of cognitively based coping strategies.

But in the end, it's this extreme specificity that's most intriguing. It could lead to a different approach to thinking about psychosis, Corlett said. The development of the visual system could be looked at more closely, along with peoples visual predictions. It could open up some basic research avenues to help gain more fundamental understanding of schizophrenia: What's the relationship between those really basic visual perceptual mechanisms and the onset of symptoms? Corlett asked. We've made very little progress in our understanding of psychosis in particular, but also in psychiatry more broadly, in terms of how these symptoms are created in the brain. I think anything that gives us inspiration, anything that might give us a bit of leverage is really, really welcomed.


In the U.S., work with schizophrenia patients has been heavily focused on cognitive tasks, like memory, Corlett said, but maybe cognitive training should include more focus on sensory factors and perception. Perhaps early visual training, along with cognitive training, could potentially help. And instead of a blood test, perhaps one day there could be an eye test for people to assess if theyre at high risk for psychosis.

Another thing to consider, which Silverstein has written about, is having people at risk for schizophrenia increase their reliance on their non-vision senses, to see if that enhances their functioning.

It's not a novel approach: to go looking for where a disease doesnt exist, in order to learn something more about it. In the 1980s and 1990s, there were people who were commonly exposed to HIV, but never developed AIDS. Studying those people led to a deeper understanding of risks, and what protective factors they may have had. It was a long-standing medical mystery that people with sickle-cell anemia were somehow protected from getting malaria. The same gene that causes abnormal red blood cells in sickle cell anemia is protective against malariaoffering a window into how malaria works in the body.

It can be difficult to study, especially for rare diseases, where you have to wait for natural cases to arise. But it can be a unique place for clues. I often joke that itd be interesting to study people like Keith Richards or Ozzy Osbourne: Why they haven't been ravaged by opiate addiction in the same way or similar addiction, Corlett said. What is it about these people that led them not to manifest illnesses? has been traditionally a very useful way of exploring what it means to be at risk and what it means to have pathophysiology.

With schizophrenia and blindness, Silverstein said were not there yet, and probably not close. That said, he doesnt think that we should ignore it.

At this point, I dont think Id go so far as to say it's promising, Silverstein said. The word Id use is intriguing. In some ways, this is one of the most interesting observations in a long time in schizophrenia research. Because its the only thing that seems to be protective against schizophrenia. I think theres something here and this should be looked into much more.

 

Re: No person born blind has ever been Schizophrenic:

Posted by alexandra_k on February 12, 2020, at 23:08:47

In reply to No person born blind has ever been Schizophrenic:, posted by PeterMartin on February 12, 2020, at 8:06:02

Hmm...

I'm not sure that I am convinced that there is an explanandum, here.

Suppose that blindness is protective against schizophrenia? Wouldn't you also expect blindess to be protective against related diagnoses such as brief episodic psychosis? I mean, there are diagnoses that are similar to schizophrenia but don't require the symptoms to be present for as long. As such, patients who are eventually diagnosed with schizophrenia are often diagnosed with several things on the way to getting to their diagnosis of schizophrenia. If that makes sense. As such, I really would expect that if it were true that blindness was protective for schizophrenia one would also expect to see that it was protective for some of those other, related, diagnoses.

So... I think the whole thing sounds fishy. That they say specifically that they did not find a negative association for those related diagnoses.

How about hallucinations? Just simple old hallucinations? They want to wax on at length about hallucinations, particularly, but apparently there wasn't a negative association for blindness and any other disorder involving hallucinations other than schizophrenia.

The whole thing sounds based on a false premise to me.

I think the sample size is likely very small. There aren't many blind people. There aren't many people with schiozphrenia. So.. There are likely only a small number of overlapping (or apparently there are none at all). Hrm.

What did they do? A literature search for 'blindness and schizophrenia' and get no hits?

Surely not.

Surely not.

Sigh.

 

Re: No person born blind has ever been Schizophrenic:

Posted by alexandra_k on February 12, 2020, at 23:13:50

In reply to No person born blind has ever been Schizophrenic:, posted by PeterMartin on February 12, 2020, at 8:06:02

Although I am wondering, now, about auditory hallucinations. Whether blind people have auditory hallucinations the way other people do.

Whether deaf people have visual hallucinations the way other people do.

It would be interesting to me, I think, whether these things occur.

 

Re: No person born blind has ever been Schizophrenic:

Posted by alexandra_k on February 12, 2020, at 23:15:24

In reply to Re: No person born blind has ever been Schizophrenic:, posted by alexandra_k on February 12, 2020, at 23:13:50

It would make more sense to me that being blind would be protective against auditory hallucination (since hearing would be more needed it might be more resilent in it's devo). Ditto for deafness being protective against visual hallucinatory experience.

Perhaps.

 

Re: No person born blind has ever been Schizophrenic:

Posted by undopaminergic on February 13, 2020, at 13:07:33

In reply to Re: No person born blind has ever been Schizophrenic:, posted by alexandra_k on February 12, 2020, at 23:13:50

> Although I am wondering, now, about auditory hallucinations. Whether blind people have auditory hallucinations the way other people do.
>
> Whether deaf people have visual hallucinations the way other people do.
>
> It would be interesting to me, I think, whether these things occur.

I think a more interesting question is whether dear people get auditory hallucinations.

-undopaminergic

 

Re: No person born blind has ever been Schizophrenic:

Posted by linkadge on February 14, 2020, at 16:11:04

In reply to Re: No person born blind has ever been Schizophrenic:, posted by undopaminergic on February 13, 2020, at 13:07:33

I think this is totally plausible.

You would only need one counterexample to disprove the assertion.

The idea that being blind from birth perhaps strengthens certain connections in the brain that help filter sensory input is also plausible.

Linkadge

 

Re: No person born blind has ever been Schizophrenic:

Posted by undopaminergic on February 15, 2020, at 3:05:34

In reply to Re: No person born blind has ever been Schizophrenic:, posted by undopaminergic on February 13, 2020, at 13:07:33


> I think a more interesting question is whether dear people get auditory hallucinations.
>

I meant"deaf" in place of "dear".

-undopaminergic

 

Re: No person born blind has ever been Schizophrenic:

Posted by Lamdage22 on February 16, 2020, at 9:03:45

In reply to Re: No person born blind has ever been Schizophrenic:, posted by undopaminergic on February 15, 2020, at 3:05:34

Thanks for clarifying. I was wondering if i should be offended.

 

Re: No person born blind has ever been Schizophrenic:

Posted by alexandra_k on February 17, 2020, at 3:07:43

In reply to Re: No person born blind has ever been Schizophrenic:, posted by undopaminergic on February 13, 2020, at 13:07:33

A person who has never been able to see doesn't know what it is like to be able to see. As such, they wouldn't be able to say whether they were having seeing-like experiences or not.

Similarly for a person who has never been able to hear and auditory-like experiences.

There is some evidence of neural plasticity so that the brain regions devoted to processing information from one source may be co-opted to processing information from a different source when that usual source is absent.

For example, if a person is born blind then the parts of their occipital cortex that would, in a sighted individual, be activated in response to visual stimuli, can, instead, come to be activated in response to auditory stimuli or tactile stimuli or vibrational stimuli.

People who are born blind develop hyper or super or special sensistivity in processing auditory / tactile / vibrational stimuli. They can sense when a person is in the room etc because they are more sensitive to / attentive to vibration.

There is some evidence that when a person experiences hallucination what is going on is that there is cortical activity without sensory input. So, for example, when a person is having an auditory hallunication they are experiencing activation of the auditory cortex but the activation is abnormal in the sense that it isn't occuring in response to external information but is being top-down driven (as it may be in dreams).

When a person thinks to themselves in words hearing or sub-vocal speech / motor areas of the cortex may be activated.

When a deaf person thinks to themselves in sign language...

Does the auditory cortex activate?

If a person is blind and they have activation to their visual processing cortex without external stimuli being present (e.g., in a dream) then what sort of experience do they have? A visual one? What sort of stimuli would trigger that activation in them if that activation was triggered by external stimuli?

I don't know.

I guess I was wondering, somehow, if all the extra brain power devoted to one modality may make it more resilient to breaking.

Like how if you are genuinely bilingual (two languages before 7ish years old) then language is more distributed in your brain so you are more resilent to losing language if you have localised trauma e.g., stroke.

 

Re: No person born blind has ever been Schizophrenic:

Posted by alexandra_k on February 17, 2020, at 3:19:38

In reply to Re: No person born blind has ever been Schizophrenic:, posted by alexandra_k on February 17, 2020, at 3:07:43

But breaking is different from activation.

Maybe.

There was something... Something I half remember.

Constant stimulation to a region can have the same effect as ablation of the region. I suppose because you are knocking out the signalling (rate firing) either way.

If we suppose that hallunications are activations of cortical regions that are associated with stimuli from external sources (but may become de-coupled in dreams or hallucinations or imagingings or rememberings or conscious experiencings)...

Then I don't suppose there is any reason to believe that deaf people or blind people would be less prone to visual or tactile hallucinations respectively.

I just don't see a deaf person reporting auditory hallunications or a blind person reporting visual hallucinations since these words wouldn't have experiences associated with them for them.

It would be like a color blind person reporting experiences of a color they couldn't see.

Hallucinate echo-location much?

 

Re: No person born blind has ever been Schizophrenic: » alexandra_k

Posted by undopaminergic on February 17, 2020, at 3:26:12

In reply to Re: No person born blind has ever been Schizophrenic:, posted by alexandra_k on February 17, 2020, at 3:07:43

Interesting post alexanda_k. How do people lacking a sensory modality dream? Do blind people "see" in dreams? Do deaf people "hear"?

Do deaf people have a "musical" experience in response to the vibrations from loud music?

-undopaminergic

 

Re: No person born blind has ever been Schizophrenic:

Posted by alexandra_k on February 17, 2020, at 7:47:55

In reply to Re: No person born blind has ever been Schizophrenic: » alexandra_k, posted by undopaminergic on February 17, 2020, at 3:26:12

I find it hard to imagine that a blind person wouldn't be able to imagine some aspects of visual experience. I imagine they use something a little more like echolocation than I am able to imagine to form... Representations of their environment. Aspects of spatial layout, I mean to say. Distance of objects.

I find it hard to imagine that a deaf person wouldn't be able to feel tap tap tappity tap tappity tap tap tap and vibrations fast and slow, deep and light to feel the music.

I don't see why they wouldn't experience these during dreaming. Have the capacity to hallucinate even.

I have a fun little game I like to play with myself sometimes. It is closing my eyes and trying to see a particular color. Red, let's say. Trying to see it with my eyes closed. I can imagine red. I can imagine red objects. Red fire engines and the like. But am I actually seeing red with my eyes closed? For me, vivid dreaming / hallucinating with my eyes closed, actually seeing without visual stimuli is something that only really happens at a certain point of drowsiness towards sleep. I get glimpses only at other times. Hard to tell if I am actually seeing with my eyes closed or imagining in a way that isn't actually a visual experience.

There was this cool little trick you could do to locate your blind spot (you have a blind spot right in the middle of your field of vision when you close one eye so binocular vision doesn't eliminate it). Once you have located it you become quite convinced that you have a blind spot. Indeed.

Only your visual field doesn't seem to contain a blind spot, to you. It feels or seems to be a complete field.

So then it seems that your brain is somehow filling in the blind spot with visual experience.

It sort of gets you thinking / realising how we don't actually see half the things we think we see.

I don't know that I am making any sense.

I just mean that a blind person wouldn't likely report visual hallucinations because if they had visual hallucinations they wouldn't have any way of knowing that they were *visual* hallucinations, particularly. I mean... How would you begin to describe visual experience to someone who didn't have it?

On the other hand... I think that description can go rather a long way. I can come to some sort of appreciation of what it is like to be a bat by 'feeling' my way there by thinking about how blind people get around. Maybe by blindfolding myself and acclimitising somewhat. Maybe by discovering how the other senses can become heightened. Not to capture it exactly...

But sort of...

Infer the missing shade of blue from examples either side.


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