URBAN LIVING --INCREASED MENTAL ILLNESS

 

Epidemiologists showed decades ago that people raised in cities are more prone to mental disorders than those raised in the countryside. But neuroscientists have avoided studying the connecting, preferring to leave the disorderly realm of the social environment to social scientists. A paper in this issue of Nature represents a pioneering foray across that divide. 

More than half of the world’s population now lives in cities, making the creation of a healthy urban environment a major policy priority..Cities have both health risks and benefits, but mental health is negatively affected: mood and anxiety disorders are more prevalent in city dwellers and the incidence of schisophrenia is strongly increased in people born and raised in cities. Although these findings have been widely attributed to the urban social environment, the neural processes that could mediate such associations are unknown. 

Using functional brain imaging, a group led by Andreas Meyer-Lindenberg of the University of Heidelberg’s Central Institute of Mental Health in Mannheim, Germany, showed that specific brain structures in people from the city and the countryside respond differently to social stress. Stress is a major factor in precipitatin g psychotic disorders such as schizophrenia. The work is a first step towards difming how urban life can affect brain biology in a way that has a potentially major impact on society schizophrenia affects one in 100 people. It may also open the way for greater cooperation between neuroscientists and social scientists. There has been a long history of mutual antipathy, particularly in psychiatry. But this is the sort of study that can prove to both sides that they can gain from each others’ insights. 

Although a dozen or so genes have been linked to the disorder, “even the most powerful of these genes conveys only a 20% increased risk”, says the report. Yet schizophrenia is twice as common in those who are city-bom and raised as in those from the countryside, and the bigger the city, the higher and risk. This report becomes all the more important in an scenario when just two years back humanity moved to an unchanered territory when there were more city dweller than rural folks on the planet. In fact with the city and the urban areas contributing to more than 70° 0 of the global GDP, employment pulls peoples in grooves to the cities. Apart from the increased instances ot'mental disease risk, at least in agrarian nations like Ind ia with the increased femin ization of agriculture, 
URBAN LIVING --INCREASED MENTAL ILLNESS  Epidemiologists showed decades ago that people raised in cities are more prone to mental disorders than those raised in the countryside. But neuroscientists have avoided studying the connecting, preferring to leave the disorderly realm of the social environment to social scientists. A paper in this issue of Nature represents a pioneering foray across that divide. 

More than half of the world’s population now lives in cities, making the creation of a healthy urban environment a major policy priority..Cities have both health risks and benefits, but mental health is negatively affected: mood and anxiety disorders are more prevalent in city dwellers and the incidence of schisophrenia is strongly increased in people born and raised in cities. Although these findings have been widely attributed to the urban social environment, the neural processes that could mediate such associations are unknown. 

Using functional brain imaging, a group led by Andreas Meyer-Lindenberg of the University of Heidelberg’s Central Institute of Mental Health in Mannheim, Germany, showed that specific brain structures in people from the city and the countryside respond differently to social stress. Stress is a major factor in precipitatin g psychotic disorders such as schizophrenia. The work is a first step towards difming how urban life can affect brain biology in a way that has a potentially major impact on society schizophrenia affects one in 100 people. It may also open the way for greater cooperation between neuroscientists and social scientists. There has been a long history of mutual antipathy, particularly in psychiatry. But this is the sort of study that can prove to both sides that they can gain from each others’ insights. 

Although a dozen or so genes have been linked to the disorder, “even the most powerful of these genes conveys only a 20% increased risk”, says the report. Yet schizophrenia is twice as common in those who are city-bom and raised as in those from the countryside, and the bigger the city, the higher and risk. This report becomes all the more important in an scenario when just two years back humanity moved to an unchanered territory when there were more city dweller than rural folks on the planet. In fact with the city and the urban areas contributing to more than 70° 0 of the global GDP, employment pulls peoples in grooves to the cities. Apart from the increased instances ot'mental disease risk, at least in agrarian nations like Ind ia with the increased femin ization of agriculture, increases the risk of debilitating diseases in female populace who have never been accustomed to the high intensive labor work that is demanded by the unmechanized agricultural production that is practiced in India. 

The finding was from a study conducted on a group of volunteers. The team scanned the brains of 32 student volunteers while they performed arithmetic tests, At the same time, the students received negative feedback through headphones. The investigating team would tell individuals they were performing below average, and suggest impatiently they hurry up a bit, so they’d feel they were failing. This ‘social stress’ activated many brain areas, two of them Specially correlated with the volunteers’ history of urban living. The amygdala, which processes emotion, was activated only in people currently living in a city. And the cingulate cortex, which helps to regulate the amygdala and processes negative emotions, responded more strongly in those brought up in cities than in those who grew up in towns or rural areas. The initial experiment showed such clear associations that Meyer-Lindenberg didn’t think anyone would believe them. So he did a similar experiment on another 23 subjects, this time adding visual feedback that allowed particiapants to see the investigators’ frowns. He found the same sturdy associations. 

He now plans to repeat the work in the general population, where urbanrural differences are likely to be even stronger than in students. He also plans to study how other risk factors identified by social scientists such as being an immigrant affect stress processing. “We will use tools from social scientists to help us quantify things like perceived discrimination, social support networks, or stigma,” he says. 

The present study has important repercussion on other domain sciences. The social sciences for example have as much to gain from crossing disciplinary boundaries as the biological sciences, says Morgan. “Sociologists and epidemiologists establish associations that are plausible like immigrants may suffer more mental illness because of social isolation but they are validated when neuroscientists demonstrate a robust biological mechanism.” For his future investigations, Meyer-Linderberg is seeking urban planners who can help him to tease out how variables such as green space and population density contribute to the neurobiological impact of city living. Hans Wirz of the urban planning office in Basel, Switzerland, says that it took comeses to integrate knowledge about the biomedical effects of the cityscape into his profession. “But when it comes to mental health we haven’t a clue.” 

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