A personal or family history of migration is an important risk factor for schizophrenia. The differential risk pattern across subgroups suggests a role for psychosocial adversity in the etiology of schizophrenia.

This meta-analysis provides evidence for a sex difference in the risk of developing schizophrenia, as reported in the published literature from the last 2 decades.

This study confirmed marked heterogeneity in risk for psychotic disorders by person and place, including higher rates in younger men, racial/ethnic minorities, and areas characterized by a lower percentage of owner-occupied houses.

The hypothesis that chronic and long-term experience of 'social defeat' may increase the risk for schizophrenia is proposed. This increased risk may result from sensitisation of the mesolimbic dopamine system and/or increased baseline activity of this system. Data supporting the social defeat hypothesis are presented.

The incidence of psychotic disorders was elevated most significantly among immigrants living in neighborhoods where their own ethnic group comprised a small proportion of the population.