Project Summary Paranoia, a core feature of psychosis and a clinically significant transdiagnostic construct, manifests dimensionally and in the population and significantly impacts social functioning and well-being across the severity spectrum. This proposal addresses critical knowledge gaps in understanding the ethnoracial dynamics contributing to the persistent observation of heightened paranoia among Black Americans compared to their White counterparts, irrespective of clinical status. Specific Aim 1 bridges current knowledge gaps by identifying both risk (e.g., past exposure to discrimination) and resilience factors (e.g., racial identity) that may mediate and moderate the relationship between race and self-reported paranoia in Black and White Americans using self-report survey methodology. To our knowledge, we are the first team to systematically investigate the intricate interplay between both individual- and group-level sociocultural factors that may influence heightened paranoia endorsements observed among Black Americans. Furthermore, while racial discrimination has been implicated as a potential driver of racial group differences in paranoia, the correlational nature of current research limits causal inferences. Specific Aim 2 addresses this limitation by employing a randomized experimental paradigm to test the causal relationship between exposure to racial discrimination and increased paranoia among Black Americans. In addition, we will meticulously examine the sociocultural factors that may influence the magnitude of experimental effects (e.g., self-reported past exposure to discrimation and racial identity), shedding light on nuanced factors at play. By elucidating these ethnoracial dynamics and causal pathways, the proposed research will refine the understanding of paranoia expression across groups—providing crucial information for culturally sensitive and accurate measurement of the psychosis spectrum within ethnoracially diverse populations.