Introduction: Racial-ethnic minority status is a consistent risk factor for schizophrenia, with associations extending to bipolar disorder and subthreshold psychotic experiences. However, few epidemiologic studies have been conducted in the U.S., and evidence is inconsistent. Furthermore, no U.S. studies of youths have directly investigated the phenomenological overlap between schizophrenia and bipolar disorder. We aimed to do so at the subthreshold level in the Philadelphia Neurodevelopmental Cohort.
Methods: Participants included 6533 individuals, age 11-21years, from a community healthcare network. Latent class analysis was used to form subtypes of sub-psychosis based on 12 attenuated positive items and 7 mania items without duration criteria. Associations between race-ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, "other") and sub-psychosis subtype were estimated using latent class regression.
Results: Four classes were identified: Sub-positive Only (13.4%), Mania Only (15.5%), Both (9.1%), and Neither (62.0%). Minority participants were generally more likely than non-Hispanic whites to belong to one of the three sub-psychosis classes compared to the Neither class. Associations for Hispanics and non-Hispanic blacks remained after adjustment for age, sex, and maternal education, and restriction to participants without significant physical health conditions. Racial-ethnic disparities were greater in magnitude for the two classes characterized by sub-positive symptoms, Sub-positive Only and Both, than for the Mania Only class. This pattern was statistically significant among non-Hispanic blacks.
Conclusions: We found evidence for racial-ethnic disparities in empirically-derived subtypes of subthreshold psychosis, broadly defined, among U.S. youths. Further research is needed to determine whether these disparities persist to the clinical disorder level in adulthood.
Keywords: Ethnicity; Mania; Psychosis; Race; Subthreshold; U.S. youths.
Published by Elsevier B.V.