Abstract
Many studies report an ethnic density effect whereby psychosis incidence among ethnic minority groups is higher in low co-ethnic density areas. It is unclear whether an equivalent density effect applies with other types of socioeconomic disadvantages. We followed a population cohort of 2 million native Danes comprising all those born on 1st January 1965, or later, living in Denmark on their 15th birthday. Socioeconomic disadvantage, based on parents' circumstances at age 15 (low income, manual occupation, single parent and unemployed), was measured alongside neighbourhood prevalence of these indices. Each indicator was associated with a higher incidence of non-affective psychosis which remained the same, or was slightly reduced, if neighbourhood levels of disadvantage were lower. For example, for individuals from a low-income background there was no difference in incidence for those living in areas where a low-income was least common [incidence rate ratio (IRR) 1.01; 95% confidence interval (CI) 0.93-1.10 v. those in the quintile where a low income was most common. Typically, differences associated with area-level disadvantage were the same whether or not cohort members had a disadvantaged background; for instance, for those from a manual occupation background, incidence was lower in the quintile where this was least v. most common (IRR 0.83; 95% CI 0.71-0.97), as it was for those from a non-manual background (IRR 0.77; 95% CI 0.67-0.87). We found little evidence for group density effects in contrast to previous ethnic density studies. Further research is needed with equivalent investigations in other countries to see if similar patterns are observed.
Highlights
Many studies report an ethnic density effect whereby psychosis incidence among ethnic minority groups is higher in low co-ethnic density areas
Elevated psychosis incidence is not apparent where migrant groups do not constitute a numerical minority (Corcoran et al, 2009). This is clearly seen at the neighbourhood level where studies consistently show that the extent to which members of an ethnic group are in a minority, i.e. their neighbourhood ethnic density, is inversely related to their psychosis risk (Bécares, Dewey, & Das-Munshi, 2018; Shaw et al, 2012)
We looked at different types of disadvantages reported as being associated with psychosis in previous studies (Byrne, Agerbo, Eaton, & Mortensen, 2004; Corcoran et al, 2009; Eaton, 1974; Hakulinen, Webb, Pedersen, Agerbo, & Mok, 2020; Morgan et al, 2008; Muntaner, Tien, Eaton, & Garrison, 1991; Werner, Malaspina, & Rabinowitz, 2007), with each measured at the parental level to preclude reverse causality
Summary
Many studies report an ethnic density effect whereby psychosis incidence among ethnic minority groups is higher in low co-ethnic density areas It is unclear whether an equivalent density effect applies with other types of socioeconomic disadvantages. Other more general explanations are proposed; for example, that this reflects more general improvements in social support, as a result of living with others with shared circumstances (Das-Munshi et al, 2010, 2012; Shaw et al, 2012) This may in turn reflect more fundamental aspects of a shared lifestyle, or ‘habitus’, and a sense of localised identity having a positive effect on overall psychological wellbeing (Bourdieu, 1984; Halpern, 1993). It is argued, a lack of fit with the neighbourhood social
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
