In a study by researchers at Columbia University Mailman School of Public Health and The Hague, Netherlands, it was cited that neighbourhood ethnic density is linked with a risk of psychosis among immigrants in the country.

It was reported in the study that immigrants who live in neighbourhoods where their own ethnic group comprise a small proportion of the population are at increased risk for certain psychotic disorders, like Schizphrenia.

The findings of the study led by Ezra Susser, chair of the Department of Epidemiology at the Mailman School of Public Health, and research scientist at the New York State Psychiatric Institute, confirmed the potential importance of environment and social experiences that may contribute to these disorders.

The study also emphasised the need for public health clinicians to focus on the mental health needs of immigrants, and highlighted the importance of cultural sensitivity when treating immigrant and minority patients.

For the study, the researchers conducted diagnostic interviews with individuals living in The Hague, Netherlands who contacted a physician for a suspected psychotic disorder over a seven-year period (1997-1999 and 2000-2005).

Later, the results were examined by ethnicity and neighborhood of residence. They defined a "high ethnic density" neighborhood as one in which 65 percent of the population was immigrant. All other neighborhoods were defined as "low ethnic density."

As against the native Dutch, the occurrence of psychotic disorders for first and second generation immigrants from Morocco, Surinam, and Turkey living in The Hague was considerably increased in low ethnic density neighborhoods.

Immigrant populations in these neighborhoods had psychotic disorders more than two times the rate of immigrants living in high ethnic density neighborhoods.

Though the findings were consistent for all three ethnic groups, Moroccans had the highest incidence of schizophrenia in both high and low density neighborhoods.

An earlier US study in the 1930s reported higher hospital admission rates for schizophrenia among ethnic minorities who lived in neighborhoods with a low proportion of persons belonging to their own ethnic group.

"It now appears they may have been right; it matters where you live. Increasingly, investigators suspected that the social experiences of immigrant groups after migration contribute to their elevated risk. However, until this body of research -- large enough to examine the incidence of psychotic disorders for immigrant groups within a single urban area -- few studies had the data to confirm that increased incidence of psychotic disorders among immigrants depended strongly on neighborhood context," said Dr. Susser.

The study is published in the recent issue of the American Journal of Psychiatry.

ANI