TY - JOUR

T1 - The ethnic density effect in psychosis: a systematic review and multilevel meta-analysis

AU - Baker, Sophie

AU - Jackson, Mike

AU - Jongsma, Hannah

AU - Saville, Christopher

N1 - Copyright © The Author(s), 2021. Published by Cambridge University Press on behalf of the Royal College of Psychiatrists

PY - 2021/12

Y1 - 2021/12

N2 - Background An ‘ethnic’ or ‘group’ density effect in psychosis has been observed whereby the risk of psychosis in minority group individuals is inversely related to neighbourhood-level proportions of others belonging to the same group. However, there is conflicting evidence over whether this effect differs between minority groups and limited investigation into other moderators.Aims To conduct a comprehensive systematic review and meta-analysis of the group density effect in psychosis and examine moderators.Method Four databases were systematically searched. A narrative review was conducted, and a three-level meta-analysis was performed. The potential moderating effect of crudely and specifically defined minority groups was assessed. Country, time, area size, and whether studies used clinical or non-clinical outcomes were also tested as moderators. ResultsThirty-two studies were included in the narrative review and ten in the meta-analysis. A ten percentage-point decrease in own-group density was associated with a 20% increase in psychosis risk [OR=1.20 (CI95%=1.09-1.32), p<0.001]. This was moderated by crudely defined minority groups [F6,68=6.86, p<0.001], with the strongest associations observed in Black populations, followed by a White Other sample. Greater heterogeneity was observed when specific minority groups were assessed [F25,49=7.26, p<0.001]. ConclusionsThis is the first review to provide meta-analytic evidence that the risk of psychosis posed by lower own-group density varies across minority groups, with the strongest associations observed in Black individuals. Heterogeneity in effect sizes may reflect distinctive social experiences of specific minority groups. Potential mechanisms are discussed, along with the implications of findings and suggestions for future research.

AB - Background An ‘ethnic’ or ‘group’ density effect in psychosis has been observed whereby the risk of psychosis in minority group individuals is inversely related to neighbourhood-level proportions of others belonging to the same group. However, there is conflicting evidence over whether this effect differs between minority groups and limited investigation into other moderators.Aims To conduct a comprehensive systematic review and meta-analysis of the group density effect in psychosis and examine moderators.Method Four databases were systematically searched. A narrative review was conducted, and a three-level meta-analysis was performed. The potential moderating effect of crudely and specifically defined minority groups was assessed. Country, time, area size, and whether studies used clinical or non-clinical outcomes were also tested as moderators. ResultsThirty-two studies were included in the narrative review and ten in the meta-analysis. A ten percentage-point decrease in own-group density was associated with a 20% increase in psychosis risk [OR=1.20 (CI95%=1.09-1.32), p<0.001]. This was moderated by crudely defined minority groups [F6,68=6.86, p<0.001], with the strongest associations observed in Black populations, followed by a White Other sample. Greater heterogeneity was observed when specific minority groups were assessed [F25,49=7.26, p<0.001]. ConclusionsThis is the first review to provide meta-analytic evidence that the risk of psychosis posed by lower own-group density varies across minority groups, with the strongest associations observed in Black individuals. Heterogeneity in effect sizes may reflect distinctive social experiences of specific minority groups. Potential mechanisms are discussed, along with the implications of findings and suggestions for future research.

KW - Ethnic density

KW - mental health inequality

KW - minority groups

KW - psychosis

KW - schizophrenia

U2 - 10.1192/bjp.2021.96

DO - 10.1192/bjp.2021.96

M3 - Article

VL - 219

SP - 632

EP - 643

JO - British Journal of Psychiatry

JF - British Journal of Psychiatry

SN - 0007-1250

IS - 6

ER -