Psychotic disorders in minority groups: the high price of being an ‘outsider’

In 1932 a psychiatrist called Ornulv Odegaard published a paper in which he reported that Norwegian immigrants in Minnesota had a much higher incidence of mental health problems than Norwegians back in their home country of Norway. The percentage of people in the Norwegian immigrant population experiencing such disorders was also much higher than it was among other minority groups in America.

“We’ve known for a long time that immigrant populations experience a greater frequency of psychotic disorders than the host population – and that it’s higher in immigrant groups than in the populations of the countries they have left,” says Hannah Jongsma, a PhD candidate in the Department of Psychiatry.

“Odegaard’s study is striking because he was the first researcher to carry out an academically robust study showing these variations. His findings were frequently interpreted to suggest a ‘selective migration’ hypothesis – and that those who migrated were somehow innately at a higher risk of developing psychotic disorders. This hypothesis has since been thoroughly tested and found to be false.”

Jongsma’s doctoral research draws on data gathered by an ambitious in-depth study of schizophrenia and other psychotic disorders in six countries. The data she uses was gathered by a project known as EU-GEI which sought to identify the interactive genetic, clinical and environmental determinants, involved in the development, severity and outcome of schizophrenia, right across the population of a number of countries.

Next week (2-6 April 2016) Jongsma will present her first findings from the EU-GEI study at the 5th Biennial Schizophrenia International Research Society Conference in Florence, Italy.  Her presentation will give an overview of the incidence rates of psychotic disorders (the number of new cases per head of the population) and look at variations between the different study settings.

“My research looks specifically at the experiences of minority communities – for example British citizens with Trinidadian heritage,” says Jongsma. “The data I’m using is from the case-control arm of the EU-GEI study and based on six-hour interviews and assessments with individuals who experienced a first episode of psychosis, their siblings and healthy controls. As far as I know, it is the most ambitious study of its kind to date, combining a rich set of socio-demographic, clinical and cognitive variables with a very large sample size – more than 2,000 people across the three groups.”

Although she has a background in public health, Jongsma’s undergraduate degree was in liberal arts and she holds a masters in philosophy. “As someone without a medical training, I was thrilled to be offered this PhD position in the Department of Psychiatry,” she says. “What I bring to my work on psychosis in minority communities is an ability to look at things from different points of view – a skill you develop when you study philosophy. I find the ability to think at different levels of abstraction has really helped my understanding of psychosis. I’m able to relate societal level variables, such as racial discrimination, to an individual’s chance of developing a psychotic disorder.”

It’s estimated that, in the UK, one in four people experience a mental health problem each year, and one in hundred will experience a psychotic disorder. Psychosis is a catch-all term that covers disorders of thought and perception that may have organic causes (such as a brain lesion or abuse of alcohol or other drugs) as well as a range of genetic components and environmental triggers. The World Health Organisation divides psychosis into affective and non-affective disorders.  Affective disorders are dominated by their effects on mood and include depression and bipolar disorder. Non-affective disorders are not dominated by their effects on mood and include schizophrenia and delusional disorders.

“It’s likely that psychosis often develops as a consequence of a cluster of factors which have a cumulative effect and stack up to have a negative effect on psychological well-being. The factors that interest me most are the cultural and societal ones,” says Jongsma. “One of the great strengths of a university as broad as Cambridge is that it encourages dialogues between, for instance, neuroscientists, geneticists and epidemiologists. For the researcher, this provides valuable opportunities to exchange and develop ideas.”

The EU-GEI data on which Jongsma is basing her research was gathered in Brazil, England, France, Italy, the Netherlands and Spain. It confirms that psychosis often presents in late adolescence and peaks in adulthood – and that men are more vulnerable. “Our data also shows that psychosis is more prevalent in urban compared to rural areas. Rural Spain showed the lowest incidence and south-east London the highest,” says Jongsma.

Research has shown that the high incidence of psychosis in minority communities is not limited to first-generation immigrants who might have experienced stress and upheaval in moving countries and finding their feet in a new culture.

“Second and subsequent generations are similarly vulnerable to higher levels of psychosis than the majority population around them. Second generation immigrants may struggle with finding a clear identity and experience a conflict in their affiliations and loyalties – on the one hand with the culture of their parents and on the other with the culture of the wider community,” suggests Jongsma. “Interestingly the density of an immigrant community sometimes seems to have a protective effect – in other words, the denser the immigrant community, the lower the level of psychosis – while sometimes the opposite is apparent.”

When a particular, and easily identifiable, community is seen to have raised levels of mental illness, there is a real danger of stereotyping. “In the UK, it is well known that psychotic disorders are particularly prevalent among Afro-Caribbeans who represent one of the largest groups of immigrants,” says Jongsma. “But, in the Netherlands, where I come from, psychosis is most common among Moroccan immigrants. To me, this suggests we need to look at the role these groups hold in society. Both minority groups suffer from deep-seated prejudices and discrimination.”

One possible reason for raised levels of psychotic disorders in minority groups is their lack of economic and social status. ‘Social defeat’ is a term coined by Professor Jean-Paul Selten (Maastricht University) and colleagues to describe the persistent negative experience of being excluded from the majority population. “This idea makes an interesting starting point for trying to understand the root causes of psychotic disorders,” says Jongsma. “Being at the lowest rung of the ladder has been shown to be stressful in primates and is likely to have the same effect on humans.”

The freedom to express cultural identity is important to mental health. “Identities are formed and maintained on the basis of complex interactions with, and imitations of, those around us – and this social aspect of identity is crucial.  Empathy with others and seeing them as fellow citizens, for example, comes from shared identity. It might be the case that minorities are excluded from the group of people regarded as fellow citizens,” says Jongsma.

With so many factors in the mix, unravelling the cause and effect of psychotic disorders will continue to present a challenge. For example, does an individual become mentally unwell as a consequence of being isolated – or does he or she withdraw as a result of being unwell?  Genetic factors play a part as do environmental factors such as childhood trauma, cannabis use and deprivation.

“One of the arguments I find very interesting to explore is that psychosocial disempowerment could be seen as an explanatory framework. Over a long period, the feeling that you’re not in control of your life, and that you’re stuck in a hopeless situation that’s unlikely to improve, has been shown to increase mortality and the chance of developing physical illnesses such as heart attacks. I think it is important to look at this in the context of mental illness too,” says Jongsma.

“Poor health is strongly linked to deprivation and inequality – and all that comes with disadvantage. This is as true for heart disease and diabetes as it is for mental illness. In order to improve public mental health, we will have to look not just at the individuals who develop psychotic disorders, but at society more broadly.”

Hannah Jongsma is attending the 5th Biennial Schizophrenia International Research Society Conference with a travel grant awarded by the organisers.