December 18, 2007

Stress of Immigration and Discrimination a Risk Factor for Schizophrenia?

New research suggests a connection between the stress of immigration and an increased risk for schizophrenia. That is, researchers have found that the immigrant experience increases the likelihood of developing schizophrenia. Now a new research study performed in the Netherlands finds that immigrants living in mixed ethnic neighborhoods are more likely to develop schizophrenia.

The study appears in this month's issue of the American Journal of Psychiatry. In it, researchers looked at first and second-generation "migrants in several neighborhoods of The Hague," and found that those participants living in mixed neighborhoods of The Hague had a greater likelihood of developing schizophrenia (as opposed to participants who lived in homogeneous neighborhoods of The Hague).

Researcher Wim Veling of Dutch mental health care provider Parnassia Navo Group found that the chances of developing schizophrenia doubled for Surinamese and Turks and multiplied by four for Moroccans if they lived in mixed Dutch-migrant residential areas.

Veiling believes that there is a connection between developing schizophrenia and having increased exposure to locals. He points out a couple of examples that he encountered in his research which demonstrate the connection: (1) Confrontation with locals increases chances of discrimination and also stress associated with discrimination which in turn contributes to the development of schizophrenia; (2) Youth may have a difficult time with identity while living in mixed neighborhoods and this may also increase their chances of developing schizophrenia.

The press release from the one of the groups involved in the study said:

In a study on neighborhood ethnic density, collaborating researchers from Columbia University Mailman School of Public Health and The Hague, Netherlands, report that immigrants who live in neighborhoods where their own ethnic group comprise a small proportion of the population are at increased risk for certain psychotic disorders. The findings confirm the potential importance of environment and social experiences that may contribute to these disorders, including schizophrenia, one of the leading causes of long-term disability. The study underscores the necessity for public health clinicians to pay attention to the mental health needs of immigrants, and highlights the importance of cultural sensitivity when treating immigrant and minority patients. The paper is published in the January 2008 issue of the American Journal of Psychiatry.

The team 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). The results were then analyzed by ethnicity and neighborhood of residence. A “high ethnic density” neighborhood was defined as one in which 65 percent of the population was immigrant; because immigrant communities in the Netherlands tend to cluster in the same areas, those neighborhoods were also ones in which the proportion of any one immigrant’s ethnic group was substantial. All other neighborhoods were defined as “low ethnic density.” Compared with native Dutch, the incidence of psychotic disorders for first and second generation immigrants from Morocco, Surinam, and Turkey living in The Hague was significantly 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. While the findings were consistent for all three ethnic groups, Moroccans had the highest incidence of schizophrenia in both high and low density neighborhoods.

A landmark U.S. 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,” said Ezra Susser, MD, DrPH, chair of the Department of Epidemiology at the Mailman School of Public Health, and research scientist at the New York State Psychiatric Institute and co-author of the study. “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,” noted Dr. Susser.

The researchers also adjusted for single marital status, which has been associated with higher rates of schizophrenia, particularly in neighborhoods with fewer single-person households. “Results remained statistically significant, indicating that the ethnic density effect cannot be attributed to a greater probability of single marital status among individuals living in low-ethnic-density neighborhoods,” according to Hans Wijbrand Hoek, MD PhD, adjunct professor of Epidemiology at the Mailman School and senior author.

Neighborhood ethnic density was assessed and investigated at the time of first treatment contact. In future studies, the researchers suggest it might be feasible to collect data on neighborhood context in childhood and adolescence. This approach could be used to determine the developmental period during which neighborhood ethnic density is most important.

Abstract: Ethnic Density of Neighborhoods and Incidence of Psychotic Disorders Among Immigrants. Veling, W., et al. (American Journal of Psychiatry)

Related Stories:
Social Stress Associated with Immigration Identified as a High Risk Factor for Schizophrenia
Social Factors in the Development of Schizophrenia: A Review of Recent Findings


I wonder if they factored in the prevalence of street drug usage within the migrant population?. It’s clear from reading the posts on this site, that there are a significant group of people who used street drugs before being diagnosed.

Posted by: heywood at December 18, 2007 04:17 PM

I wonder why these articles never state more specific statistical info
about the immigrant status of the subjects. I always wonder how
recently the subjects immigrated.

Also, these types of studies still seem to be jumping to conclusions
based on frontloaded superficial observations. Where are the stats about the genetic family history of the subjects.

Frankly, I have often wondered if there is something in the sz spectrum that is more likely to be present in those who are disposed toward migrating. What was the reason for the subjects
migrating? What were the cultural/familial conditions present in the
life of such subjects before they migrated in the first place. Are the
subjects first generation migrants. Are they second generation? What is
the likelyhood that immigrants will find mates in a very small restrictive
pool of people of similar background or ethnicity. How long has that gene
pool of people been present? These are all questions I would want answers
to if I were involved in such research.

Posted by: JEN at December 31, 2007 05:49 PM

Putting aside the genetic question (because I am not really sure that it is all that pertinent...)one can ask the question "Is there something in the idea of emigrating/leaving the country that is intrinsic to the experience of schizophrenia ?" i.e. the idea of feeling foreign among others, the search for a new place where one can feel at home to replace an old one which is associated with traumatic experiences. If this is the case, then the correlation noted between schizophrenia and migration could be explained by a preexisting disposition towards schizophrenia (declared or not, that is to say, with active symptoms or not) among a given percentage of the immigrant population.

Posted by: Debbie at January 1, 2008 01:22 PM

Yes but the title of the article goes further than that, it suggests that discrimination by the settled Dutch population is so severe that it is causing an unusually high percentage of immigrants to become mentally ill.
I would suggest that if that is the unlikely case, that the pressures from other ethnic groups living in ghetto areas are just ikely to be the cause, and not as this article suggests that the pressure is from the indigenous white Dutch population.

Posted by: heywood at January 1, 2008 03:52 PM

I think it goes something like this-
You get bullied, oppressed
You prepare to receive insults, hassle
Bullying, oppression becomes normal, feeling bad becomes normal
Your brain ,in order that it is comfortable with the familiar, finds ways of making insults to you under the guise of hearing negative voices.
This stress created causes escalation of symptoms.

Posted by: Josh at January 2, 2008 02:16 PM

There is something else about the migrant experience : migrants find themselves caught between two different languages, cultures, two different ways of organizing human experience in a way to give it meaning. Perhaps they are more likely to fall through the cracks, given the fact that some of them were "rootless" even before leaving their home country. Such a legacy wreaks havoc with the following generations.

Posted by: Debbie at January 3, 2008 09:56 AM

I dont know about the claims in this post. I am living the life of--I dont need to conduct a study to make observations; hence my observations come from more direct real world contact. My husband is first generation pakistani american - we live in a very mixed neighborhood. External factors do not have as big an impact on adpatation as this study makes it sound like-- adaptability is related to the family's openness to the local culture. If the family puts one in the middle--and makes them feel guilty to integrate into local culture THAT IS THE ROUTE CAUSE OF STRESS AND HEARTACHE THAT MAY LEAD TO SCHIZO LIKE THINKING.. NOT THE LOCAL ENVIRONMENT ITSELF>

Posted by: sq at January 10, 2008 03:05 PM

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