Impaired social functioning is commonly observed in youth at clinical high risk (CHR) for psychosis. Interpersonal synchrony, defined as the temporal alignment of movement between interacting partners, is a key component of successful social interactions. This study aimed to investigate interpersonal head synchrony in naturalistic virtual settings among CHR individuals using automated video analysis tools.

We analyzed short video recordings from virtual clinical interviews involving 116 participants including 50 CHR participants, 36 individuals with sub-threshold positive symptoms (SUB), and 30 healthy controls (HC). Vertical head movement time series were extracted using an open-access video-based head-tracking tool. Interpersonal head synchrony was computed using Windowed Cross-Correlation to assess group differences and associations with clinical symptoms and functioning.

CHR participants showed significantly reduced strength of synchrony compared to HC (β = −0.05, 95% CI [−0.09, −0.02], p = .004), although 14% of variance in strength of synchrony was attributable to assessor identity. No significant group differences were found for delay of synchrony. Within the CHR group, delay of synchrony was positively associated with social anhedonia (r = 0.29). Strength of synchrony correlated with better social (r = 0.33) and role (r = 0.28) functioning.

Our findings suggest that impaired interpersonal head synchrony is already present in the psychosis-risk state and relates to negative symptoms and social and role functioning. These findings support the utility of nonverbal synchrony as a potential biomarker and demonstrate the feasibility of automated tools and virtual assessments to study social processes in at-risk populations.