Attributing Schizophrenia To Income Inequality (Instead Of The Other Way Around)
    By News Staff | December 14th 2012 11:00 AM | 3 comments | Print | E-mail | Track Comments

    Higher rates of schizophrenia are found in urban areas and it can be attributed to increased deprivation, increased population density and an increase in inequality within a neighborhood, says a new paper.

    In common tongue, that used to be called putting the cart before the horse.  A cliché among people who know just enough science to be wrong, you will read 'correlation does not equal causation', and for a more thoughtful examination, you can read how autism can be 'attributed' to the rise if organic food and the Arab spring can be attributed to the price of steel in the same way this study attributes schizophrenia to income inequality, rather than that schizophrenics simply tend to make less money because they are schizophrenic.

    How was that determined? Social environment assessments of people who claimed a psychotic disorder. They used data from a population-based incidence study (the East London first-episode psychosis study directed by Professor Jeremy Coid at the East London NHS Foundation Trust and Queen Mary, University of London) conducted in three neighboring inner city, ethnically diverse boroughs of East London: City&Hackney, Newham, and Tower Hamlets.

    427 people aged 18-64 years old, all of whom experienced a first episode of psychotic disorder in East London between 1996 and 2000, were assessed about their social environment through measures of the neighborhood in which they lived at the time they first presented to mental health services because of a psychotic disorder. Using the 2001 census, they estimated the population aged 18-64 years old in each neighborhood, and then compared the incidence rate between neighborhoods.  

    They concluded that the incidence of schizophrenia (and other similar disorders where hallucinations and delusions are the dominant feature) still showed variation between neighborhoods after taking into account age, sex, ethnicity and social class. Three environmental factors predicted risk of schizophrenia – 'deprivation', such as unemployment, income, education and crime, along with increased population density and an increase in inequality (the gap between the rich and poor).

    This suggested that a percentage point increase in either neighborhood inequality or deprivation was associated with an increase in the incidence of schizophrenia and other similar disorders of around 4%. 

    Dr. James Kirkbride, principal investigator and lead author of the paper from the University of Cambridge, said, "Our research adds to a wider and growing body of evidence that inequality seems to be important in affecting many health outcomes, now possibly including serious mental illness. Our data seems to suggest that both absolute and relative levels of deprivation predict the incidence of schizophrenia. East London has changed substantially over recent years, not least because of the Olympic regeneration. It would be interesting to repeat this work in the region to see if the same patterns were found."

    They further conclude that risk of schizophrenia in some migrant groups might depend on the ethnic composition of their neighborhood. For black African people, they found that rates tended to be lower in neighborhoods where there were a greater proportion of other people of the same background. By contrast, rates of schizophrenia were lower for the black Caribbean group when they lived in more ethnically-integrated neighborhoods. They say the findings support the possibility that the socio-cultural composition of our environment could positively or negatively influence risk of schizophrenia and other similar disorders. 

    "Although we already know that schizophrenia tends to be elevated in more urban communities, it was unclear why. Our research suggests that more densely populated, more deprived and less equal communities experience higher rates of schizophrenia and other similar disorders. This is important because other research has shown that many health and social outcomes also tend to be optimal when societies are more equal," said Kirkbride.

    Published in Schizophrenia Bulletin.


    I wonder though, if it's not an "attribution" that we should be looking for, and more of a correlation. We all know that correlation does not equal causation... Perhaps we have more visible episodes of schizophrenia in lower income areas due to the lack of treatment? No or inadequate insurance means less therapy for medication prescriptions. I agree that this inequality is a piece of the puzzle, but not the ultimate cause. The roots go deeper... it could be hereditary. People with schizophrenia are less successful financially and end up in lower income areas, having children with a higher risk for developing schizophrenia. It's a lot to think about and consider, but the relationship is definitely there!

    Sure, but they are trying to say that income inequality is a cause, which is a little silly. Obviously people with a mental health issue are going to be at a greater risk of being unstable and unable to hold high-paying jobs. It can happen, but it is going to be worldwide news if a CEO of a company is schizophrenic. 
    John Hasenkam
    Difficult. It is not inconceivable though that chronic deprivation will increase the rates of psychiatric and behavior disorders. The issue is not income inequality it is income inadequacy. The physiological changes that can occur with sustained deprivation. Some of these changes if sustained over years clearly have implications for behavior and cerebral health. 
    Schizophrenia is perceived as a neuro-developmental disorder of mixed etiology. There is too much noise in the schizophrenia data to think clearly about it but various studies have highlighted a wide range of causal factors, from emigration to marijuana usage, and in the latter case considerable controversy still revolves around marijuana as a primary causal agent or being significant for only those susceptible to psychosis. I'm going for the latter because if marijuana was a direct causal agent schizophrenia rates should move with marijuana usage. The rates don't, they are remarkably stable at circa 1%. If we can't even sort this issue out after so much research we should be very cautious about determining causal agency in schizophrenia. 

    Fortunately this is a blog so I'll throw caution to the wind. The recent work of Adele Diamond is a striking demonstration of how early developmental environments can profoundly affect adult behavior, intelligence, propensity towards drug addiction, and risk for mental illness. There is a great deal of supporting research but Diamond's research indicated that the effects of severe deprivation on childhood cerebral development was in some cases so severe as to leave those children with EEGs broadly equivalent to those who had experienced frontal lobe injury. 

    It is speculated that schizophrenia becomes apparent in the latter teenage years because this is when the frontal lobes begin to "fire up". In one striking study I read years ago the MRI revealed that in those with early onset schizophrenia there was a large wave of apoptosis(programmed cell death) across the frontal neocortex in particular. This happens to everyone at that age but in the schizophrenics the cell death rate was much higher. Diffuse frontal lobe brain damage. 

    As a culture we celebrate those who come from the impoverished areas and rise above their past. The praise is ok but let's keep in mind that statistically time and again we see striking evidence that income inadequacy sets in chain series of processes that can have profoundly debilitating effects on the individuals so exposed. Income equality is a must, some deserve more, so much is obvious, but income inadequacy has so many costs we must always be looking for ways to overcome it.