The most remarkable recent epidemiologic finding relates to migrants: Some fall ill with schizophrenia not only at higher rates than the compatriots they leave behind, but at higher rates than the natives of the countries to which they have come. Dark-skinned migrants to Europe, mostly from the Caribbean or sub-Saharan Africa, are at risk of developing schizophrenia at rates as much as 10 times higher than those of white Europeans. This is a dramatic increase, and it has been shown by so many studies conducted with such methodological care that it cannot be dismissed as diagnostic racism, as if white clinicians confronted with angry black men simply called them “schizophrenic” (even though this sometimes happens). Nor does it seem that biology alone can explain the increased risk, although serious research is now being done to test the hypothesis that vitamin D deficiency plays a role.
Some observers think that the epidemiologic finding is a stark story about the way racism gets under the skin and drives people mad. It is probably more complicated than that. Another young anthropologist, Johanne Eliacin, spent two years doing fieldwork among African-Caribbean migrants living in London. Eliacin saw racism, and she felt viscerally her subjects’ stinging sense of being unwanted and out of place. But she also saw a social world shot through with hostility and anger, in which people were isolated and often intensely lonely. The African-Caribbean people in Tottenham spoke of there being no community in the community. They held up schizophrenia as the symbol of what had gone wrong. Yes, racism lay at the root of the problem, but the tangible distress was the sense of being hopelessly trapped.
Epidemiologists have now homed in on a series of factors that increase the risk of developing schizophrenia, including being migrant, being male, living in an urban environment, and being born poor. One of the more disconcerting findings is that if you have dark skin, your risk of falling victim to schizophrenia increases as your neighborhood whitens. Your level of risk also rises if you were beaten, taunted, bullied, sexually abused, or neglected when you were a child. In fact, how badly a child is treated may predict how severe the case of an adult person with schizophrenia becomes—and particularly, whether the adult hears harsh, hallucinatory voices that comment or command. The psychiatrist Jean-Paul Selten was the first to call this collection of risk factors an experience of “social defeat,” a term commonly used to describe the actual physical besting of one animal by another. Selten argued that the chronic sense of feeling beaten down by other people could activate someone’s underlying genetic vulnerability to schizophrenia.