Linking interpersonal childhood adversity to mental health: A scoping review of trust, mentalizing, agency and interpersonal emotion regulation as candidate social-transactional mechanisms

Objectives: The neurocognitive social-transactional model posits that interpersonal adversity during childhood heightens risk for mental health difficulties by altering how individuals engage with their social world. We conducted a scoping review to map current evidence for four candidate mechanisms, Trust, Mentalizing, Agency and Interpersonal Emotion Regulation (IER), linking interpersonalchildhood adversity to mental health outcomes.Methods: We systematically searched four databases and identified quantitative studies that measured interpersonal childhood adversity, one or more of the candidate mechanisms, and mental health outcomes in the same sample. A second reviewer independently assessed 10% of records at each screening stage.Results: 78 studies met inclusion criteria. For Trust (15 studies), interpersonal childhood adversity was associated with greater distrust and credulity which in turn predicted internalizing, externalizing and personality disorder symptoms. For Mentalizing (37 studies), it was associated with heightened uncertainty and reduced accuracy in understanding mental states, which was consistently linked withinternalizing, externalizing, psychosis and personality disorder symptoms. For Agency (26 studies), it was associated with a more external locus of control, which was associated with internalizing and psychosis symptoms. Evidence for IER was limited (3 studies) but suggested potential links to internalizing symptoms. Across mechanisms, findings were largely cross-sectional and based on self-report, with few longitudinal or task-based studies.Conclusion: Trust, Mentalizing and Agency emerged as promising transdiagnostic social-transactional mechanisms through which interpersonal childhood adversity shapes mental health outcomes, with more limited evidence for IER. Despite methodological gaps, these mechanisms may represent tractable targets for intervention research and trauma-informed clinical practice.