Sleep disturbance and inflammation as determinants of social cognition and behavior: An intensive longitudinal study of adults with schizophrenia-spectrum disorders - ABSTRACT People with schizophrenia-spectrum disorders (SSDs) experience significant deficits in social cognition. Social cognition independently contributes to real-world outcomes, including social competence and social functioning. As such, social cognition is an important treatment target in SSDs. Yet, current research has not adequately focused on determinants of social cognition, and intervention efforts do not reliably improve functional outcomes or produce durable gains. This study addresses that gap by examining sleep disturbance and inflammation as novel determinants of social cognition in people with SSDs. Up to 80% of people with SSDs experience sleep disturbance, which is linked to increased symptomatology, risk for suicide attempts, and reduced functional capacities and quality of life. Sleep disturbance is also linked to heightened inflammation in those with SSDs and other severe mental illnesses, like bipolar disorders (BDs), including increased C-reactive protein (CRP) and interleukin (IL)-6. Inflammation is elevated in people with SSDs and BDs, and experimental studies in healthy groups show that increased inflammation causes reduced social behavior and social cognition. While a small body of literature links sleep disturbance and inflammation to neurocognitive domains in SSDs, the relationships between sleep disturbance, inflammation, and social cognition are unexplored. This study will use an intensive longitudinal approach to 1) test the relationships between sleep disturbance, inflammation, and social cognition and behavior in those with SSDs, BDs, and healthy control (HC) participants; 2) compare SSD, BD, and HC participants on social cognition, inflammation, and ecologically assessed sleep and social parameters; and 3) develop methods to ecologically assess social cognition and use those methods to explore stability of social cognition as a day-to-day process. Twenty-five participants will be recruited per group (N=75) and asked to wear actigraphs and complete daily surveys (7 per day) over a period of 14 days, followed by a comprehensive social cognitive assessment. Dried blood spots will be collected pre- and post-intensive longitudinal data collection to provide inflammation data. Results will inform social cognitive intervention targets for SSDs and BDs (consistent with the NIMH 2020 Strategic Plan) and support a larger, definitive R01 application. Additionally, consistent with the aims of the Research Enhancement Award Program (REAP), this study will provide ample training opportunities for graduate and undergraduate students, tailored to provide exposure to groups with severe mental illnesses and training in social cognitive research methodology, intensive longitudinal assessment of biobehavioral processes, and collection and analysis of inflammation data. This project will significantly improve the research environment at the University of Southern Mississippi and establish infrastructure to support future projects, leading to a lasting positive impact on the research environment and student opportunities in the USM Clinical Psychology PhD Program.
