Child abuse is associated with a wide range of mental disease including psychotic disorders. Few studies have investigated the role of child abuse in contributing to increase the risk of psychosis in migrant population.

To explore the risk of first episode psychosis (FEP) in migrants and natives for each type of trauma i.e. physical abuse (P.A.), sexual abuse (S.A.), emotional abuse (E.A.), physical neglect (P.N.) and emotional neglect (E.N.).

Within a large case- control incidence sample of FEP from the EU-GEI study (The EUropean Network of National Schizophrenia Networks Studying Gene–Environment Interactions) we evalued the assocition of childhood trauma with FEP in migrants and natives. Associations were adjusted for age, gender, social status, level of education, family history of psychosis and cannabis use. Trauma was assessed through Childhood Trauma Questionnaire (CTQ).

CTQ mean score was higher in FEP migrants (45.4, sd 15.6) than in FEP natives (41.7, sd 13.9) (p = 0.002). In natives every type of child abuse was associated with FEP. In migrants P.A., S.A., P.N. were associated with FEP. We found a dose – dependent relationship between trauma and FEP.

Child abuse is common in individuals with psychosis. FEP migrants are more exposed to childhood trauma. Clinicians should routinely assess patients for childhood trauma. When treating a FEP migrant patient, clinicians must be aware of an underlying traumatic childhood adversity more than of a traumatic migration history.

Psychosis rates are higher among some migrant groups. We hypothesized that psychosis in migrants is associated with cumulative social disadvantage during different phases of migration.

We used data from the EUropean Network of National Schizophrenia Networks studying Gene-Environment Interactions (EU-GEI) case–control study. We defined a set of three indicators of social disadvantage for each phase: pre-migration, migration and post-migration. We examined whether social disadvantage in the pre- and post-migration phases, migration adversities, and mismatch between achievements and expectations differed between first-generation migrants with first-episode psychosis and healthy first-generation migrants, and tested whether this accounted for differences in odds of psychosis in multivariable logistic regression models.

In total, 249 cases and 219 controls were assessed. Pre-migration (OR 1.61, 95% CI 1.06–2.44, p = 0.027) and post-migration social disadvantages (OR 1.89, 95% CI 1.02–3.51, p = 0.044), along with expectations/achievements mismatch (OR 1.14, 95% CI 1.03–1.26, p = 0.014) were all significantly associated with psychosis. Migration adversities (OR 1.18, 95% CI 0.672–2.06, p = 0.568) were not significantly related to the outcome. Finally, we found a dose–response effect between the number of adversities across all phases and odds of psychosis (⩾6: OR 14.09, 95% CI 2.06–96.47, p = 0.007).

The cumulative effect of social disadvantages before, during and after migration was associated with increased odds of psychosis in migrants, independently of ethnicity or length of stay in the country of arrival. Public health initiatives that address the social disadvantages that many migrants face during the whole migration process and post-migration psychological support may reduce the excess of psychosis in migrants.