June 13, 2006

Urban Schizophrenia Risk: A Family Affair?

A new article on the Schizophrenia Research Forum web site discusses the well-known link between urban living and increased risk for schizophrenia.

They note:

Children born and raised in cities grow up to develop schizophrenia at a higher rate than their country-dwelling counterparts. While the evidence implicates environmental factors, no specific exposures have been identified that can explain the urban-rural difference. But because the urban environment acts on both children and their families, it stands to reason that environmental effects act on the level of the family to contribute to the increased risk of schizophrenia in cities. ...

The [new research] results point to the family situation as an important locus for environmental insults, but what kinds of exposure could cause the differences observed? Parental education level is one possibility to explain family-related risk, but Pedersen and Mortensen say the reported effects are too small to be the only explanation for their findings. They suggest several possibilities, including maternal lead exposure, toxoplasmosis, or infections in siblings that would affect fetal development or be transmitted years later.

One intriguing possibility to explain these results is a twist on selective migration — the idea that individuals at risk for schizophrenia preferentially migrate to urban areas, while mentally healthy people do not. Selective migration of individuals clearly cannot explain the higher risk of schizophrenia among children born in the city. But selective migration operating at the level of families might. In that case, families carrying some unknown risk for schizophrenia might also tend to settle in urban areas, where they raise at-risk children. To advance understanding the urban-rural differences, direct measurements of genes and environmental factors associated with schizophrenia risk will be needed, Pedersen and Mortensen conclude.

Read the full article (its written for schizophrenia researchers, so you may find it rather technical): Urban Schizophrenia Risk: A Family Affair?


Very interesting topic, but how come the authors didn't include enviromental factors in their study. We all know differences between city and village enviroments. For the first, general level of noise in cities is much higher, there are a lot less relaxing factors, like greenery, sounds of nature, smels of nature, in the cities then in the villages. Instead city children are constantly exposed to stress, in the shape of too many people they meet, too many information they have to process etc. They become less aware of their self. From my expirience, noise plays important role in symptoms shizophrenia.


Posted by: maria at June 14, 2006 11:46 PM

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