Neighbourhood Ethnic Density and Incidence of Psychosis – First and Second Generation Migrants Compared

Abstract

Introduction

Living in an area with few people from the same ethnic background has been associated with increased incidence of psychosis (the ethnic density effect).

Objectives

Compare associations between neighbourhood ethnic density and incidence of non-affective psychosis for first and second generation migrants.

Methods

Population based cohort (2.2 million) of all those born 1st January 1965 or later and living in Denmark on their 15th birthday. We looked at a total of 106,000 migrants, including 62% first generation migrants. Ethnic density was determined at age 15 and we adjusted for age, gender, calendar period, parental psychiatric history and parental income at age 15.

Results

For the first generation, we found no evidence that rates of non-affective psychosis were related to neighbourhood ethnic density for migrants from Africa (comparing lowest and highest quintiles): IRR 1.02 (95% CI 0.6–1.73), and the Middle East: IRR 0.96 (CI 0.68–1.35) and only weak evidence for migrants from Europe (excluding Scandinavia): IRR 1.35 (CI 0.98–1.84). Conversely, for the second generation rates of non-affective psychosis were increased for migrants from Africa in lower ethnic density neighbourhoods (comparing lowest and highest quintiles): IRR 3.97 (95% CI 1.81–8.69), Europe (excluding Scandinavia): IRR 1.82 (CI 1.28–2.59) and the Middle East: IRR 2.42 (CI 1.18–4.99).

Conclusions

There is strong evidence for an area ethnic density effect on psychosis incidence for second generation migrants, but not for first generation migrants. This could reflect a greater resilience among the latter group to the adverse effects of minority status.

Disclosure of interest

The authors have not supplied their declaration of competing interest.