This is now about six years old but it remains one of the better meta analyses of a risk factor — being a migrant — and risk of psychosis. The abstract here helps. The paper is of reasonable quality.

There is increasing acceptance of migration as a risk factor for schizophrenia and related disorders; however, the magnitude of the risk among second-generation immigrants (SGIs) remains unclear. Generational differences in the incidence of psychotic disorders among migrants might improve our understanding of the relationship between migration, ethnicity and psychotic disorders. This meta-analysis aimed at determining the risk of psychotic disorders among SGIs in comparison with non-migrants and first-generation immigrants (FGIs).
Medline, EMBASE and PsycINFO databases were searched systematically for population-based studies on migration and psychotic disorders published between 1977 and 2008. We also contacted experts, tracked citations and screened bibliographies. All potential publications were screened by two independent reviewers in a threefold process. Studies were included in the meta-analysis if they reported incidence data, differentiated FGIs from SGIs and provided age-adjusted data. Data extraction and quality assessment were conducted for each study.
Twenty-one studies met all inclusion criteria. A meta-analysis of 61 effect sizes for FGIs and 28 for SGIs yielded mean-weighted incidence rate ratios (IRRs) of 2.3 [95% confidence interval (CI) 2.0–2.7] for FGIs and 2.1 (95% CI 1.8–2.5) for SGIs. There was no significant risk difference between generations, but there were significant differences according to ethno-racial status and host country.
The increased risk of schizophrenia and related disorders among immigrants clearly persists into the second generation, suggesting that post-migration factors play a more important role than pre-migration factors or migration per se. The observed variability suggests that the risk is mediated by the social context.

Bourque, F., Van der Ven, E., & Malla, A. (2011). A meta-analysis of the risk for psychotic disorders among first- and second-generation immigrants. Psychological Medicine, 41(5), 897-910. doi:10.1017/S0033291710001406

Interestingly, this increase in prevalence is, for Northern Africans, primarily male and is not reflected among people with psychosis in North Africa. It occurs in the immigrant population.

Epidemiological studies in the Netherlands have reported an excessive gender gap in the risk for non-affective psychotic disorder (NAPD) among immigrants from Morocco with a higher risk elevation in males compared to females. We examined the consistency of these findings and their generalizability to immigrants from the Maghreb (Mauritania, Morocco, Algeria, Tunisia and Libya) in other European countries.

Systematic review and meta-analysis. Medline, PsychINFO and EMBASE databases were searched for publications in the period from January 1970 to April 2014. We included incidence and prevalence studies of non-affective psychotic disorder (NAPD) among migrants from the Maghreb in Europe and studies of subclinical psychotic symptoms (SPS) in representative samples. A meta-analysis was performed on the subgroup of incidence studies.

Five incidence and three prevalence studies of NAPD, and two prevalence studies of SPS, conducted in the Netherlands (n=7), Belgium (n=1), France (n=1) and Italy (n=1) met our inclusion criteria. Across all research designs, the risks of NAPD and SPS were consistently increased among male, not female immigrants from the Maghreb. The meta-analysis of incidence studies of NAPD yielded male-to-female risk ratios of 5.1 [95 % confidence interval (CI) 3.1–8.4] for migrants from the Maghreb, 2.0 (95 % CI 1.6–2.5) for other migrant groups, and 1.8 (95 % CI 1.3–2.5) for non-migrant Europeans.

The marked gender gap in psychosis risk among migrants from the Maghreb appears a consistent finding, foremost among the Moroccan-Dutch. The small number of studies limits the strength of conclusions that can be drawn about countries other than the Netherlands. Achievement–expectation mismatch, social marginalization and an increased prevalence of illicit drug use are possible explanations.

van der Ven, E., Veling, W., Tortelli, A. et al. Soc Psychiatry Psychiatr Epidemiol (2016) 51: 1603. doi:10.1007/s00127-016-1261-0

Migration is bad for your risk of psychosis. And it is bad for your sons. It is better to stay in your native land: the exception is if you are the group that has taken over the native land: the Engish in Canada, Auatralia and New Zealand have a lower risk of psychosis than the indigenous.