Physiological and social synchrony as markers of PTSD and resilience following chronic early trauma

Objective Although resilience is a key topic in clinical theory and research, few studies focused on biobehavioral mechanisms that underpin resilience. Guided by the biobehavioral synchrony frame, we examined the dynamic interplay of physiological and behavioral synchrony as marker of risk and resilience in trauma-exposed youth. Methods A unique cohort of war-exposed versus control children was followed at four time-points from early childhood to preadolescence and child posttraumatic stress disorder (PTSD) repeatedly assessed. At preadolescence (11-13 years), mother and child were observed in several social and nonsocial tasks while cardiac data collected and measures of respiratory sinus arrhythmia (RSA) and RSA synchrony computed. The social interactive task was microcoded for behavioral synchrony and the second-by-second balance of behavioral and physiological synchrony was calculated. War-exposed preadolescents were divided into those diagnosed with PTSD at any time-point across childhood versus resilient children. Results Group differences in behavioral synchrony, RSA synchrony, and their interplay emerged. PTSD dyads exhibited the tightest autonomic synchrony combined with the lowest behavioral synchrony, whereas resilient dyads displayed the highest behavioral and lowest autonomic synchrony. Hierarchical Linear Model analysis pinpointed two resilience-promoting mechanisms. First, for resilient and control dyads, moments of behavioral synchrony were coupled with decreased RSA synchrony. Second, only among resilient dyads, moments of behavioral synchrony increased child RSA levels. Conclusion Findings specify mechanisms by which biobehavioral synchrony promotes resilience. As children grow, the tightly coupled mother-child physiology must be replaced by loosely coordinated behavioral attunement that buttresses maturation of the child's allostatic self-regulation. Our findings highlight the need for synchrony-based interventions to trauma-exposed mothers.