It has been said that schizophrenia strikes without regard to sex, race, social class, or culture. Whoever said that must be crazy: it’s far from true. Schizophrenia is more common in men than women – about 1.4 to 1. It’s more common in the lowest SES groups, although that may be downward drift. Schizophrenia is considerably more common among people of African ancestry. In the US, about 3 times more common. It seems that immigrants are more vulnerable, all else equal: that might be because crazy people are more likely to pull up stakes, or maybe being a stranger and afraid in a world you never made is bad for your mental health. Schizophrenia seems to be more common among people that grew up in cities – about twice as common. If we took this risk as seriously as teeny-tiny / uncertain dietary cancer risks, the freeways tomorrow morning would be clogged with frantic refugees fleeing the caves of steel.
African immigrants to Europe and Great Britain are much more vulnerable to schizophrenia. In the UK, blacks (from the Caribbean) have a seven to ten-fold increased risk. Interestingly, this actually seems to get worse in the second generation.
This would be more interesting if schizophrenia was a natural category, easy to definitively diagnose. There’s something there, surely, but clean-cut it’s not. There is reason to suspect that people researching mental illness are crazier than average: this hasn’t helped.
Many – most! – of the articles addressing the higher rate of diagnosed schizophrenia among blacks attribute it to clinician bias. Jonathan Metzl has written a whole book on this thesis: The Protest Psychosis. Judging from those high rates in Afro-Caribbeans (as much as 15 times higher !) British psychiatrists must be the world’s most rabid rednecks. They probably begin therapy by making the patient squeal like a pig. But psychiatrists in the US must be highly racist as well. Somehow this has escaped the stereotype factory: that isn’t the way psychiatrists portrayed on the big screen. It’s more about eating someone’s liver “with some fava beans and a nice Chianti”, or stalking Capucine.
If we understood mental illness better, these epidemiological patterns would probably be telling us something interesting.. As it is, I’m not sure.