SPONTANEOUS INTERPERSONAL SYNCHRONY IN BIPOLAR DISORDER AND SCHIZOPHRENIA ACROSS TRIVIAL AND INTIMATE CONVERSATIONS

This study presents findings on the morphological and temporal patterns of Spontaneous Interpersonal Synchrony (SIS) in patients with Bipolar Disorder (BD) and Schizophrenia (SZ), as well as their first-degree biological relatives, during conversations with a healthy control about trivial and intimate topics. Interpersonal synchrony refers to the degree to which individuals’ behaviors within a social interaction become coordinated in time and form. It is considered a core behavioral marker of interpersonal attunement, closely linked to empathy, cooperation, and social-cognitive functioning. Although previous research has documented alterations in social cognition and in non-spontaneous interpersonal synchrony in clinical groups with autism spectrum disorder, schizophrenia, and social anxiety, little is known about SIS in these populations. In particular, the temporal and morphological dynamics of SIS in individuals diagnosed with BD and SZ remain largely unexplored. The sample consisted of 200 adults: 25 with BD, 25 relatives of individuals with BD, 25 with SZ, 25 relatives of individuals with SZ, and 100 healthy controls matched for age, sex, and education. Dyads composed of a patient or relative and a healthy control participated in two 15-minute conditions: (1) conversation about trivial topics and (2) conversation about intimate topics. Interactions were recorded using a motion capture system (OptiTrack) and analyzed using cross-correlations to detect bodily coupling. Differences in the morphological and temporal patterns of SIS were observed as a function of diagnosis and conversation topic. These findings are discussed in relation to neural and behavioral mechanisms supporting affective attunement across meaningful social contexts.