Within-person associations of daily activity to sleep actigraphy following trauma: Explicating a novel index of risk for major depressive disorder and posttraumatic stress disorder.

Adult patients (N = 206) were recruited in-hospital following traumatic events resulting in significant physical injury (e.g., motor-vehicle crashes, violence) for a longitudinal investigation of adjustment. Approximately 4-5 months posttraumatic event, participants completed a diagnostic interview (Structured Diagnostic Interview for the Diagnostic and Statistical Manual of Mental Disorders-5-Research Version; First et al., 2015) and approximately 10 days of passive biosensing, using an Actigraph GT9X (ActiLife Software). Data were extracted and processed, and within-person, bidirectional associations between sleep constructs (sleep fragmentation, efficiency) and daily activity (total step count, sedentary time periods) were estimated via linear-mixed effects models (Bolger & Laurenceau, 2013). No self-report of sleep or activity was included in the primary analyses, only passive-sensing data. Within-person estimates (extracted as random effects) of sleep-activity indices (SAI) were considered in relation to current continuous symptoms of major depressive disorder and posttraumatic stress disorder, derived from diagnostic interviews. Two SAI indices were uniquely predictive of either major depressive disorder or posttraumatic stress disorder symptoms, even when considering past diagnoses and a range of relevant covariates and survived Type 1 error correction. These SAI indices may represent novel patterns of vulnerability following trauma and may offer new pathways for treatment and risk reduction. (PsycInfo Database Record (c) 2025 APA, all rights reserved).