Momentary Temporal Associations Among Sleep Disturbances, Eating Disorder Behaviors, and Suicidal Ideation in Anorexia Nervosa Spectrum Disorders

OBJECTIVE: Anorexia nervosa spectrum disorders (ANSD) are associated with high chronicity and mortality, with suicidality representing one of the most common and clinically significant comorbidities. Sleep disturbances are prevalent in individuals with ANSD and have independently been linked to both eating disorder (ED) symptom severity and suicidal ideation (SI), yet their temporal role in maintaining ANSD symptoms and SI remains poorly understood. This study examined sleep disturbances as a potential shared, transdiagnostic mechanism contributing to daily fluctuations in ANSD symptoms and SI. METHOD: Participants meeting diagnostic criteria for ANSD with current or past SI (n = 128) completed daily ecological momentary assessment (EMA) surveys assessing sleep disturbances, ED symptoms, and SI. Analyses and hypotheses were pre-registered. RESULTS: Multilevel models tested within- and between-person, temporally lagged, bidirectional associations among sleep disturbances, ANSD symptoms, and SI. Greater sleep disturbances predicted increased next-day restriction, binge eating, compensatory behaviors, body checking, and SI. Bidirectional effects were also observed, such that elevations in restriction, binge eating, compensatory behaviors, body checking, and SI predicted greater sleep disturbances the following night. DISCUSSION: These findings suggest that sleep disturbances are dynamically embedded in the daily maintenance of core ANSD symptoms and SI. Sleep may represent a shared, modifiable vulnerability process contributing to ANSD severity and SI, highlighting its potential as a transdiagnostic intervention target in both eating disorder treatment and suicide prevention.