Being racially or ethnically discriminated against may increase the risk of later developing psychotic symptoms, finds a major review of international evidence led by UCL (University College London) researchers.
The authors of the new umbrella review, published in PLOS Mental Health, found consistent evidence from numerous studies that racial and ethnic discrimination appears to contribute to the development of psychosis.
The findings help to explain previously reported elevated rates of psychotic disorders among ethnic minority groups.
The researchers, based at UCL and King's College London, reviewed evidence from seven published systematic reviews and meta-analyses that covered a total of 23 primary studies with 40,300 participants in Europe and the US.
Many studies identified a positive relationship between racial or ethnic discrimination and psychosis, which is a mental state where someone loses touch with reality, experiencing symptoms such as hallucinations, delusions, confused thinking, and disorganised behaviour. These symptoms underlie severe mental health conditions such as schizophrenia.
Notable prior findings highlighted in the review are that people who have experienced discrimination are 77% more likely to experience psychotic symptoms, and are nearly twice as likely to have a psychotic experience as those who have not. People who have experienced a physical racial attack are five times more likely to experience psychotic symptoms later on.
The largest effect sizes were observed in non-clinical samples in the general population, in people who did not have a psychotic disorder but were experiencing psychotic experiences and symptoms linked to racial/ethnic discrimination they had experienced.
First author, PhD student India Francis-Crossley (UCL Division of Psychiatry) said: "By pulling together the best available evidence, we have shown that there is a clear link between experiencing racial or ethnic discrimination and subsequent risk of psychosis. Experiencing discrimination can have a real and profound impact on a person's mental health, and these findings help us to understand the serious health inequities in psychosis rates.
"While our review did not investigate specifically why discrimination might increase the risk of psychosis, there is evidence that consistent stress of experiencing racism can lead to changes in the brain and impact how our brains process threats."
The researchers say that direct discrimination is but one factor that can impact the risk of psychosis among minority ethnic groups.
India Francis-Crossley added: "Our review was only looking at the impact of a person directly perceiving racism or interpersonal racial/ethnic discrimination; it may be that systemic racism, which can go unseen but still have profound impacts, could further contribute to mental health disparities."
Senior author Professor James Kirkbride (UCL Division of Psychiatry) adds: "While our review finds that experiences of racism are linked to greater psychosis risk, too little is being done in public health and policy to tackle this societal scourge, resulting in both the breakdown of civic trust and perpetuation of intergenerational disparities in serious mental health conditions between different ethnic groups."
Senior author Dr Juliana Onwumere (Institute of Psychiatry, Psychology & Neuroscience, King's College London) said: "Racism is a global threat to society. This review shines a spotlight on the threat it poses to our mental health. This review offers different messages, including ideas for further studies. However, a message that should not be overlooked is that racism is neither inevitable nor a disease but if left unchecked its human costs are substantial."
The study was supported by Windsor Fellowship, Wellcome, National Institute for Health and Care Research, and UK Research and Innovation.
