4 ms·

"Living in an urban environment during childhood or as an adult has consistently been found to increase the risk of schizophrenia by a factor of two."[0] While

by ipnon 4y ago

"Living in an urban environment during childhood or as an adult has consistently been found to increase the risk of schizophrenia by a factor of two."[0] While city life is as complex of a confounding factor as anything, the fact that they found hunter-gatherers have practically no incidence of SZR is interesting. Is the modern megalopolis simply too intense of a stimulus for the minds of the sensitive to handle without splitting into pieces? [0] https://en.wikipedia.org/wiki/Schizophrenia#Environmental https://en.wikipedia.org/wiki/Schizophrenia#Environmental

m0llusk 4y ago
The effect is stronger than that as it scales with population densities. Geoffrey West's works explore this in some detail.
nine_k 4y ago
Does schizophrenia occur more often in people with certain genetic traits? Does the majority of people with such traits live in urban environments, e.g. in highly urbanized countries? (No idea; just a hypothesis to test.)
- jamiek88 4y ago
  More likely to be diagnosed in a city too I would imagine.
diyseguy 4y ago
Hunter gatherer societies no doubt considered them to be shamans or treated them with psychedelics
- kayodelycaon 4y ago
  I'm bipolar and I'd definitely would be a shaman or prophet. I've got the right balance of intelligence and crazy for it.
- tiahura 4y ago
  Or pushed them off a cliff.
retrac 4y ago
I suspect, if this effect is real, it has more to do with social supports, the size of the social group, and maybe also metaphysical/religious beliefs and attitudes. People who have a worldview like "Demonic possession is real! And no big deal! Happpens to everyone from time to time!" skew non-urban. They may well interact, socially and emotionally speaking, with schizophrenic relatives and community members, in a better and healthier way, than we, in all our enlightenment, do. A case of minor thought disorder, for example, can probably either be aggravated or lessened based on the social response to it. The secular Westerner may not think schizophrenics are demon-possessed, but we sure tend to treat them like they are cursed.
- hindsightbias 4y ago
  I read an article once about treatment of schizophrenics in an African country. Basically put in a single cage but monitored and treated well. Westerners saw it as barbaric, but the local culture saw them as being possessed in a good or bad way and most recovered in a month and there was a ceremony to welcome them back from their journey. No negative societal MH stigma attached to it. Medically, not sure about it, but culturally seems more mature than we have.
bodhiandphysics 4y ago
I think a more likely reason why hunter gatherers don't have aren't prone to schizophrenia (in this model) is that it was evolutionarily bread out of them. Hunter gatherers in the modern world are extremely weird populations that are often under intense selective pressure!
ksaxena 4y ago
This may be better explained by the Hygiene hypothesis - hunter-gatherers get exposure to all sorts of microbes and parasites early in their life while city-dwellers could be shielded from equivalent exposure. See: https://en.wikipedia.org/wiki/Hygiene_hypothesis https://en.wikipedia.org/wiki/Hygiene_hypothesis
JamesLeonis 4y ago
The study directly tackles this question in section 3, including why it is very rare in hunter-gatherer societies. > We suggest that one reason why the prevalence of psychosis among people with hunter-gatherer and traditional lifestyles is so much lower than in people with contemporary western lifestyles is due to chronic stress and low-grade systemic inflammation caused by western lifestyle. Why is chronic stress important? It brings impaired immune response and chronic inflammation. This lets a number of parasites through the door, one of which is _Toxoplasma gondii_, the mind-control parasite that causes mice to not fear cats. > In light of the parasite x genotype x stress model, a probable explanation for why living in cities increases the risk of schizophrenia is increased chronic stress caused by urban living (see Lederbogen et al., 2011). City living is associated with increased amygdala activity and affects the perigenual anterior cingulate cortex, a key region for regulation of amygdala activity, negative affect, and stress (Lederbogen et al., 2011). Functional magnetic resonance imaging research has shown that city living and urban upbringing are associated with altered neural processing of acute social stress (Lederbogen et al., 2011). There is also substantial evidence indicating that visiting green spaces and being exposed to natural environments reduce psychological stress (Ewert and Chang, 2018). > Living in cities can increase contact with Toxoplasma gondii through domestic cats because cats have a more limited choice of defecation sites in urban areas (Torrey and Yolken, 2014). Likewise, it is possible that the high prevalence of schizophrenia among people with contemporary western lifestyles compared to hunter-gatherers might be caused by the higher prevalence of domestic cats and diseases associated with them. It is also possible that contemporary western lifestyles and living in cities negatively influence gut health and gut microbiota (Fig. 1). Further evidence for this hypothesis comes from findings showing that people with hunter-gatherer lifestyles have more diverse microbiota than people with contemporary western lifestyles (Sanchez-Quinto et al., 2020, Segata, 2015, Singh et al., 2019, Yatsunenko et al., 2012).

by ipnon 4y ago

m0llusk 4y ago

The effect is stronger than that as it scales with population densities. Geoffrey West's works explore this in some detail.

nine_k 4y ago

Does schizophrenia occur more often in people with certain genetic traits? Does the majority of people with such traits live in urban environments, e.g. in highly urbanized countries? (No idea; just a hypothesis to test.)

jamiek88 4y ago
More likely to be diagnosed in a city too I would imagine.

diyseguy 4y ago

Hunter gatherer societies no doubt considered them to be shamans or treated them with psychedelics

kayodelycaon 4y ago
I'm bipolar and I'd definitely would be a shaman or prophet. I've got the right balance of intelligence and crazy for it.
tiahura 4y ago
Or pushed them off a cliff.

retrac 4y ago

I suspect, if this effect is real, it has more to do with social supports, the size of the social group, and maybe also metaphysical/religious beliefs and attitudes. People who have a worldview like "Demonic possession is real! And no big deal! Happpens to everyone from time to time!" skew non-urban. They may well interact, socially and emotionally speaking, with schizophrenic relatives and community members, in a better and healthier way, than we, in all our enlightenment, do. A case of minor thought disorder, for example, can probably either be aggravated or lessened based on the social response to it. The secular Westerner may not think schizophrenics are demon-possessed, but we sure tend to treat them like they are cursed.

hindsightbias 4y ago
I read an article once about treatment of schizophrenics in an African country. Basically put in a single cage but monitored and treated well. Westerners saw it as barbaric, but the local culture saw them as being possessed in a good or bad way and most recovered in a month and there was a ceremony to welcome them back from their journey. No negative societal MH stigma attached to it. Medically, not sure about it, but culturally seems more mature than we have.

bodhiandphysics 4y ago

I think a more likely reason why hunter gatherers don't have aren't prone to schizophrenia (in this model) is that it was evolutionarily bread out of them. Hunter gatherers in the modern world are extremely weird populations that are often under intense selective pressure!

ksaxena 4y ago

This may be better explained by the Hygiene hypothesis - hunter-gatherers get exposure to all sorts of microbes and parasites early in their life while city-dwellers could be shielded from equivalent exposure. See: https://en.wikipedia.org/wiki/Hygiene_hypothesis https://en.wikipedia.org/wiki/Hygiene_hypothesis

JamesLeonis 4y ago

The study directly tackles this question in section 3, including why it is very rare in hunter-gatherer societies. > We suggest that one reason why the prevalence of psychosis among people with hunter-gatherer and traditional lifestyles is so much lower than in people with contemporary western lifestyles is due to chronic stress and low-grade systemic inflammation caused by western lifestyle. Why is chronic stress important? It brings impaired immune response and chronic inflammation. This lets a number of parasites through the door, one of which is _Toxoplasma gondii_, the mind-control parasite that causes mice to not fear cats. > In light of the parasite x genotype x stress model, a probable explanation for why living in cities increases the risk of schizophrenia is increased chronic stress caused by urban living (see Lederbogen et al., 2011). City living is associated with increased amygdala activity and affects the perigenual anterior cingulate cortex, a key region for regulation of amygdala activity, negative affect, and stress (Lederbogen et al., 2011). Functional magnetic resonance imaging research has shown that city living and urban upbringing are associated with altered neural processing of acute social stress (Lederbogen et al., 2011). There is also substantial evidence indicating that visiting green spaces and being exposed to natural environments reduce psychological stress (Ewert and Chang, 2018). > Living in cities can increase contact with Toxoplasma gondii through domestic cats because cats have a more limited choice of defecation sites in urban areas (Torrey and Yolken, 2014). Likewise, it is possible that the high prevalence of schizophrenia among people with contemporary western lifestyles compared to hunter-gatherers might be caused by the higher prevalence of domestic cats and diseases associated with them. It is also possible that contemporary western lifestyles and living in cities negatively influence gut health and gut microbiota (Fig. 1). Further evidence for this hypothesis comes from findings showing that people with hunter-gatherer lifestyles have more diverse microbiota than people with contemporary western lifestyles (Sanchez-Quinto et al., 2020, Segata, 2015, Singh et al., 2019, Yatsunenko et al., 2012).