A systematic review and meta-analysis of the ethnic density effect in psychotic disorders

A number of studies have found an ethnic density effect in psychotic disorders, where the incidence for ethnic minorities increases as the neighbourhood proportional ethnic composition decreases [Morgan and Hutchinson, Psychol Med 40:705-709, (2010); Singh, Psychol Med 39:1402-1403, (2009); Schofield et al., Psychol Med 41:1263-1269, (2010)]. However, there is a mixed picture with some studies reporting no effect [Schofield et al., Psychol Med 41:1263-1269, (2010)]. This review aimed to establish the existence of the effect by answering the review question: is there an ethnic density dose effect in the prevalence of psychotic disorders?