A review (2015) exploring the association between ethnicity, mental health problems and socioeconomic status found people from black ethnic minority backgrounds to have a higher prevalence of psychosis compared with the white majority population. This effect was still observed after controlling for socioeconomic status.
Reference: Qassem, T., Bebbington, P., Spiers, N., McManus, S., Jenkins, R., & Dean, S. (2015). Prevalence of psychosis in black ethnic minorities in Britain: Analysis based on three national surveys. Social Psychiatry and Psychiatric Epidemiology, 50(7), 1057–1064.