Identification of Factors to Predict Transition to Schizophrenia in Subjects with Ultra-high Risk for Psychosis: A Protocol for a Multicenter, Longitudinal Study of Sleep Parameters and Cytokine Levels.

Objective: Schizophrenia is a major psychiatric illness which mostly begins in adolescence and leads to impairments of social functioning. Some patients with schizophrenia have been associated with ultra-high risk state for psychosis (UHR), a condition used to operationally represent the prodromal stage of the illness. In previous studies, the UHR and the progression to overt psychosis has been reported to be accompanied with alterations in the quality of sleep and the immune system, as represented by change of blood levels of cytokines. Currently, biomarkers to predict the development of psychosis in persons at UHR have not yet reached a steady consensus. Therefore, we present a study protocol to explore predictors of transitions to psychosis, in the realm of monitoring of sleep condition and cytokine measurement, in subjects with the UHR.

Methods: This is a multicenter, longitudinal cohort study participated by 7 hospitals in Japan. We will recruit 50 UHR people and 30 healthy volunteers as a control group, and measure positive symptom, depressive symptoms, cognitive function, and social function. Blood cytokines levels and sleep indices, as well as actigraphy data will be monitored. After the baseline assessment, clinical symptoms, sleep indices, and cytokine levels will be measured every 12 weeks for 52 weeks. Actigraphy devices will continue to be worn for 52 weeks, while social function will be assessed over 104 weeks. The results of this study are expected to facilitate the development of novel intervention therapies to reduce the risk of psychosis and improve functional outcomes.