Experiences in close relationships, interpersonal trust and OXTR expression in individuals with childhood maltreatment

Social cognition is essential for forming and maintaining intimate relationships. Individuals with a history of childhood maltreatment (CM) often show impairments in interpersonal functioning, including trust and romantic attachment. The oxytocin system has been implicated in social behavior, yet the role of oxytocin receptor (OXTR) gene expression in CM-related social functioning remains insufficiently understood. This study examined the impact of CM on social cognition in a large web-based sample and explored the association between CM and OXTR gene expression in a well-characterized clinical cohort. Both studies were preregistered (https://doi.org/10.17605/OSF.IO/KNC2X), and data and code are available at OSF (https://doi.org/10.17605/OSF.IO/4DZWK). Study 1 assessed the relationship between CM severity, interpersonal trust, and romantic attachment in a web-based sample (N = 252). Participants completed the Childhood Trauma Questionnaire, the Generalized Trust Scale, a behavioral distrust game, and the Experiences in Close Relationships Questionnaire. Study 2 analyzed OXTR gene expression in peripheral blood samples from N = 92 CM-exposed individuals and examined associations with self-reported CM severity. Exploratory analyses additionally included measures of interpersonal sensitivity, social functioning, and maladaptive personality traits. In Study 1, greater CM severity was significantly associated with lower interpersonal trust (both self-reported and behavioral), and with higher levels of attachment-related anxiety and avoidance. In Study 2, no significant association was found between CM severity and OXTR gene expression in blood. However, exploratory analyses revealed that CM severity was associated with social interaction difficulties, while OXTR gene expression was associated with the maladaptive personality trait of detachment. The findings highlight robust associations between CM and impairments in trust as well as insecure romantic attachment. Although no direct link was found between CM and OXTR expression, future research should investigate gene–environment interactions using larger samples and alternative tissue sources. Interventions targeting trust and attachment processes may offer promising avenues to improve relational functioning in individuals with a history of CM.