The association of social inequality with the onset, persistence, and progression of psychotic experiences along the extended psychosis phenotype: a 6-year follow-up study in a community-based sample.

Purpose: This paper aims to investigate associations between early childhood and current indicators of socioeconomic inequality and the onset (incident), persistence and progression (increase in severity) of psychotic experiences (PEs) in a longitudinal follow-up of a community-based population.

Methods: Households in the metropolitan area of Izmir, Turkey were contacted in a multistage clustered probability sampling frame, at baseline (T, n = 4011) and at 6-year follow-up (T, n = 2185). Both at baseline and follow-up, PEs were assessed using Composite International Diagnostic Interview 2.1. The associations between baseline socioeconomic features and follow-up PEs were analysed using logistic regression models. Indicators of social inequality included income, educational level, current socioeconomic status (SES), social insurance, the area resided, ethnicity, parental educational level, and SES at birth.

Results: The risk of onset of PEs was significantly higher in lower education, lower SES, and slum-semi-urban areas. The persistence of PEs was significantly associated with the lowest levels of education and current SES, and rural residency. Persistent PEs were significantly and negatively associated with paternal SES at birth. Progression of PEs was significantly higher among respondents with educational achievements lower than university level and lower levels of SES, who have no social insurance and who reside in slum-semi-urban areas. Parental education and paternal SES at birth were not associated with the persistence of PEs.

Conclusion: Indicators of social inequality (low education, low SES, low income, and poverty in the neighbourhood) were associated with the onset and persistence of PEs and progression along the extended psychosis phenotype. The early indicators seem to have a modest life-long impact on the psychosis phenotype.