Interpersonal head synchrony in youth at clinical high risk for psychosis during emotional conversations with a close relationship partner

Interactive partners have a tendency to align their movements in time during conversation. Known as interpersonal synchrony , this key component of social interaction remains understudied in youth at clinical high risk (CHR) for psychosis, especially in naturalistic and emotional rich interactive contexts. This gap is particularly relevant given the broad alterations in interpersonal functioning in this population. The present study investigated interpersonal synchrony between head movements during three 10-minutes videotaped dyadic conversations (i.e., neutral, conflict, and pleasant) between CHR youth and a close relationship partner as well as typically developing youth and a close relationship partner. The sample consisted of 126 participants, including 29 CHR–Partner dyads and 34 Control–Partner dyads. Head movements were extracted using an open-access video-based tracking tool, and interpersonal head synchrony was computed using Windowed-Cross Correlation analysis. Results revealed that CHR-Partner dyads exhibited reduced strength of interpersonal synchrony (t = −2.07, p < .05, d = −0.53) and increased temporal delay (t = 2.78, p < .05, d = 0.71) compared to Control–Partner dyads during pleasant conversations, but not during neutral or conflict conversations. Importantly, no group differences were observed in overall head movement. Additionally, no significant associations were found between interpersonal head synchrony and clinical symptoms or social functioning. These findings demonstrate that interpersonal head synchrony alterations in CHR can emerge in pleasant interactions with familiar partners. Interpersonal head synchrony may thus represent an ecologically valid, context-sensitive feature in psychosis risk, bridging affective, motor, and interpersonal processes, although longitudinal studies are needed to establish its predictive value.