Paranoid ideation is a significant contributor to disability for individuals living with psychosis spectrum disorders such as schizophrenia. Despite its profound clinical significance, the factors which drive increases in paranoid ideation in daily life remain incompletely understood. Over the past decade, there has been an accumulation of compelling evidence demonstrating that neighborhood characteristics such as neighborhood deprivation, disorder, crime, and lack of green space contribute to psychosis spectrum symptomatology, including paranoid ideation. While informative, there are several limitations to the current literature on neighborhood environment and paranoid ideation. Most research in this area relies on aggregate diagnostic measures or broad positive symptoms ratings rather than specifically examining paranoid ideation. Additionally, novel strategies which combine methodological approaches to assess neighborhood-level risk factors for paranoid ideation, including using both geocoding and publicly available databases, have been called for. Finally, there is a need to directly examine whether increases in threat perceptions resulting from neighborhood factors are merely secondary to psychosis or whether the environment has an independent role in increasing paranoid ideation. In response to NIMH Strategic Objective 3.2 “developing strategies for tailoring existing interventions to optimize outcomes,” this study aims to illuminate how neighborhood environmental factors contribute to momentary paranoid ideation so that these factors can be considered when tailoring interventions to optimize outcomes. The proposed study will leverage data from an ongoing NIH-funded research study of the sponsor (Blanchard) to address the current gaps in our understanding of how neighborhood environment impacts momentary paranoid ideation. An innovative multimethod approach which combines geospatial data, smartphone ecological momentary assessment, virtual neighborhood audits, virtual neighborhood visits by naïve raters, and self- report data will allow us to address the following specific aims: 1a) Examine how exposure to neighborhood characteristics as defined by census block contributes to momentary paranoid ideation, 1b) assess the contribution of hyperlocal neighborhood characteristics on paranoid ideation, and 2) determine whether neighborhood factors evoke threat perceptions among non-clinical observers. Findings from this project have the potential to deepen our understanding of the role that neighborhood environment plays in the maintenance of paranoid ideation. This study builds upon my extensive experience collecting diagnostic and behavioral data from individuals with psychosis along with experience working with EMA data. Additionally, this project provides an exceptional vehicle for training in spatial epidemiological data collection, management, and analysis techniques necessary to examine environment as a social determinant of mental health a...