Nav: Home

Study shows biological changes that could underlie higher psychosis risk in immigrants

January 10, 2017

TORONTO, Jan. 10, 2017 - A new study could explain how migrating to another country increases a person's risk of developing schizophrenia, by altering brain chemistry.

Immigrants had higher levels of the brain chemical dopamine than non-immigrants in the study, conducted by the Centre for Addiction and Mental Health (CAMH) in Toronto and the Institute of Psychiatry, Psychology and Neuroscience, King's College London in the U.K. Abnormal dopamine levels are linked to symptoms of schizophrenia. Dopamine is also connected to the body's stress response.

The study was published in the January issue of Schizophrenia Bulletin.

"Schizophrenia is still a rare diagnosis," says Dr. Romina Mizrahi, a senior author and Clinician Scientist in the Campbell Family Mental Health Research Institute at CAMH. "But if we can understand the factors that increase the risk of this serious illness among immigrants, we can develop strategies such as social supports to mitigate this risk."

As Canada's population and workforce will decline without migration, a set number of immigrants are accepted into the country each year. While it's not feasible to offer stress supports to all newcomers, the approach of identifying those at highest risk and offering evidence-based interventions to prevent schizophrenia is one that Dr. Mizrahi applies to her work with youth, as Head of the Youth Psychosis Prevention Clinic and Research Program.

The current study involved a type of brain imaging called positron emission tomography (PET), and applied two different approaches to examining dopamine levels.

In Toronto, 56 study participants were given a mild stress test to see its effect on dopamine release. People with schizophrenia, and those at high risk, release more dopamine with this test when compared to a matched healthy group of participants. Among the 25 immigrants in the study, dopamine release was higher than 31 non-immigrant participants. This increase was related to participants' experiences of social stress, such as work overload, social pressures or social isolation.

The London researchers showed that the synthesis of dopamine was higher in immigrants. This increase was related to the severity of symptoms among those considered at high risk of developing schizophrenia, and did not occur among non-immigrants at high risk. In total, 32 immigrants and 44 non-immigrants were involved in this part of the study.

Dr. Mizrahi emphasizes that not everyone with high dopamine levels will develop schizophrenia, nor will the vast majority of migrants.

Yet it is well-established through population studies in Canada, the U.K. and Western Europe that the risk of developing schizophrenia is higher in immigrants and their children than non-immigrants. Stress - particularly related to perceived discrimination, social isolation and urban living - is believed to increase this risk. The role of stress also appears to be supported by the current findings on brain dopamine levels.

"This is a first step in integrating social science and biological research," says Dr. Mizrahi. "A next step would be to help regulate stress among higher risk immigrants through social support programs, and see if this reduces dopamine in the brain and prevents psychosis."
-end-
Links:

http://www.camh.ca/en/research/about_research_at_CAMH/scientific_staff_profile/Pages/Romina-Mizrahi.aspx

http://www.camh.ca/en/hospital/about_camh/newsroom/news_releases_media_advisories_and_backgrounders/current_year/Pages/Some-immigrants-and-refugees-are-at-higher-risk-of-psychotic-disorders-compared-to-the-general-Ontario-population.aspx

For more information, please contact:

Sean O'Malley
Media Relations, CAMH
416-595-6015
sean.omalley@camh.ca

The Centre for Addiction and Mental Health (CAMH) is Canada's largest mental health and addiction teaching hospital and a world-leading research centre in this field. CAMH combines clinical care, research, education, policy development and health promotion to help transform the lives of people affected by mental illness and addiction. CAMH is fully affiliated with the University of Toronto, and is a Pan American Health Organization/World Health Organization Collaborating Centre. For more information, please visit camh.ca or follow @CAMHnews and @CAMHResearch on Twitter.

Centre for Addiction and Mental Health

Related Schizophrenia Articles:

Unlocking schizophrenia
New research, led by Prof. LIU Bing and Prof. JIANG Tianzi from the Institute of Automation of the Chinese Academy of Sciences and their collaborators have recently developed a novel imaging marker that may help in the personalized medicine of psychiatric disorders.
Researchers discover second type of schizophrenia
In a study of more than 300 patients from three continents, over one third had brains that looked similar to healthy people.
New clues into the genetic origins of schizophrenia
The first genetic analysis of schizophrenia in an ancestral African population, the South African Xhosa, appears in the Jan.
Dietary supplement may help with schizophrenia
A dietary supplement, sarcosine, may help with schizophrenia as part of a holistic approach complementing antipsychotic medication, according to a UCL researcher.
Schizophrenia: Adolescence is the game-changer
Schizophrenia may be related to the deletion syndrome. However, not everyone who has the syndrome necessarily develops psychotic symptoms.
Study suggests overdiagnosis of schizophrenia
In a small study of patients referred to the Johns Hopkins Early Psychosis Intervention Clinic (EPIC), Johns Hopkins Medicine researchers report that about half the people referred to the clinic with a schizophrenia diagnosis didn't actually have schizophrenia.
The ways of wisdom in schizophrenia
Researchers at UC San Diego School of Medicine report that persons with schizophrenia scored lower on a wisdom assessment than non-psychiatric comparison participants, but that there was considerable variability in levels of wisdom, and those with higher scores displayed fewer psychotic symptoms.
Recognizing the uniqueness of different individuals with schizophrenia
Individuals diagnosed with schizophrenia differ greatly from one another. Researchers from Radboud university medical center, along with colleagues from England and Norway, have demonstrated that very few identical brain differences are shared amongst different patients.
Resynchronizing neurons to erase schizophrenia
Today, a decisive step in understanding schizophrenia has been taken.
Genetics researchers close in on schizophrenia
Researchers at the MRC Centre for Neuropsychiatric Genetics and Genomics at Cardiff University have discovered 50 new gene regions that increase the risk of developing schizophrenia.
More Schizophrenia News and Schizophrenia Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.