Neighbourhood ethnic density and psychosis — Is there a difference according to generation?

Abstract

BackgroundFor different migrant groups living in an area with few people from the same ethnic background is associated with increased psychosis incidence (the ethnic density effect). We set out to answer the question: are there generational differences in this effect?MethodsAnalysis of a population based cohort (2.2 million) comprising all those born 1st January 1965, or later, living in Denmark on their 15th birthday. This included 90,476 migrants from Africa, Europe (excluding Scandinavia) and the Middle East, with 55% first generation and the rest second-generation migrants. Neighbourhood co-ethnic density was determined at age 15 and we adjusted for age, gender, calendar period, parental psychiatric history and parental income.ResultsFor first-generation migrants from Africa, there was no statistically significant difference (p = 0.30) in psychosis rates when comparing lowest with highest ethnic density quintiles, whereas the second generation showed a 3.87-fold (95% CI 1.77–8.48) increase. Similarly, for migrants from the Middle East, the first generation showed no evidence of an ethnic density effect (p = 0.94) while the second showed a clear increase in psychosis when comparing lowest with highest quintiles, incidence rate ratio (IRR) 2.43 (95% CI, 1.18–5.00). For European migrants, there was some limited evidence of an effect in the first generation, (IRR) 1.69 (95% CI, 1.19–2.40), with this slightly raised in the second: IRR 1.80 (95% CI, 1.27–2.56).ConclusionsWe found strong evidence for an ethnic density effect on psychosis incidence for second-generation migrants but this was either weak or absent for the first generation.

Change in incidence rates for psychosis in different ethnic groups in south London: findings from the Clinical Record Interactive Search-First Episode Psychosis (CRIS-FEP) study

“…Despite the increase in the white non-British population in the UK, particularly since the expansion of the European Union in 2004 and ease of migration from Eastern Europe, we found weak evidence of increased risk of psychosis between the white non-British and white British ethnic groups. Our findings in this group are in keeping with two recent studies (Kirkbride et al, 2017;Schofield et al, 2017), which both found that non-British white ethnic groups in the UK and migrants from elsewhere in Europe to Denmark were not at increased risk of psychosis. This may also be because the white non-British patients may experience a less stressful acculturation process and lower perceived discrimination (Schofield et al, 2017) within Europe.…”

A comprehensive systematic review and multilevel meta-analysis of the ethnic density effect in psychosis

“…Fourteen studies were conducted (45%) in the UK 9,11,[25][26][27][28][29][30][31][32][33][34][35][36] , eight (26%) in the Netherlands [37][38][39][40][41][42][43][44] , and four (13%) in Sweden [45][46][47][48] . Of the remaining five (16%), two were conducted in Denmark 49,50 , and one of each in the USA 51 , Canada 52 , and Australia 53 .…”

“…The majority were retrospective epidemiological studies (n=26, 84%) 9,11,[25][26][27][28][29][30][31][32][33][34][35][36][39][40][41][42][45][46][47][48][49][50]52,53 . Of these, most were cross-sectional and six (four datasets) used longitudinal methods 32,[46][47][48][49][50] . All of these studies were conducted in a neighbourhood context with the exception of one which considered a school setting 46 .…”

“…Around half of the studies (n=15, 48%) examined first incident cases 9,[25][26][27]31,35,36,39,41,42,[45][46][47]49,50 and six (19%) used measures of subclinical psychosis 11,[28][29][30]33,51 . The others assessed symptomatic outcomes 37,38,43,44 , mortality rates 32 , inpatient days following admission 34 , compulsory admission 48 , individuals meeting ultra-high risk [UHR] criteria 53 , dispensed antipsychotic medication 40 , lifetime prevalence of psychosis 52 , psychophysiological outcomes 43 , and social distance 43,44 .…”

“…Fourteen studies (twelve datasets) included Black individuals 11,25,[27][28][29][30][31][32][33]39,40,47,49,50 . Significant group density associations were found in aggregated Black or Black British clinical and non-clinical samples in the UK 27,28 .…”