The general aim of this study is to explore the prevalence of major depressive disorder and the use of mental health services in the immigrant populations in the Metropolitan Region of Santiago, Chile.

The hypotheses are:

1. A healthy immigrant effect will be observed in the studied population by which their prevalence of major depressive disorder will be lower than the prevalence in the general Chilean population.
2. A significant association will be observed between the loss of socio-economic position after migration and a greater probability of major depressive disorder.
3. A significant association will be observed between the report of victimization experience(s) in the previous year and a greater probability of major depressive disorder.
4. A significant association will be observed between financial difficulties and a greater probability of major depressive disorder.

The sampling framework of the Chilean National Institute of Statistics (INE) from the 2016 Census will be used for the purpose of this research. The sampling units are as follows:

1. Primary sampling units (PSUs): conglomerates or groups of adjoining houses, organized in spatial blocks (200 households on average)
2. Secondary sampling units (SSUs): individual households within each of the conglomerates selected in the first stage
3. Final sampling units: persons meeting the study's inclusion criteria Multi-stage random probability sampling involving a 3-stage sampling design will be used - first, the sampling of the primary sampling units (PSUs); second, the sampling of households within the selected PSUs and finally, the random sampling of a household member.

Participants (n=1,100) will then take part in a 45-minute interview. This interview will be a household survey using the modular version of the Composite International Diagnostic Interview (WHO-CIDI) looking at exploring a broad spectrum of factors traditionally associated with increased risk of affective disorders:

1. Sociodemographics
2. Finance
3. Variation in socioeconomic position
4. Experience of victimization
5. Discrimination
6. Experience of childhood adversity

Inclusion Criteria:

• Country of birth other than Chile
• Time since arrival to Chile: 3 months

Exclusion Criteria:

• Unable to understand Spanish

Adults residing in private households in the Metropolitan Region of Santiago, Chile who were born outside of Chile and have lived in the country for at least 3 months

IPD (database, dictionary) will be made available to researchers upon request.

3 years after data collection ends

Researchers with interest in mental health, particularly migration mental health