Childhood trauma, peripheral inflammation, and neurocircuit alterations: a structured narrative review of transdiagnostic pathways

Childhood trauma is a major transdiagnostic risk factor for persistent affective, motivational, and cognitive symptoms, yet the biological processes that translate early exposure into later neurobehavioral vulnerability remain incompletely defined. This structured narrative review evaluates peripheral inflammation as one context-dependent contributor and organizes the literature across four evidence links: childhood trauma to peripheral inflammatory activity; peripheral inflammation to neurocircuit function; childhood trauma to neurocircuit alterations; and same-sample multi-node evidence spanning at least three components of the trauma–immune–circuit/behavior–symptom framework, with temporal ordering evaluated separately. The synthesis distinguishes childhood maltreatment from broader early-life adversity and treats threat and deprivation as overlapping dimensions rather than mutually exclusive categories. Current subtype-sensitive evidence does not establish a robust threat–deprivation distinction in inflammatory associations, given exposure co-occurrence, heterogeneous measurement, and residual confounding. Inflammation-to-circuit evidence is comparatively convergent for selected reward-related endpoints, including monetary-reward activation and corticostriatal connectivity; symptom associations include anhedonia in selected samples. Anticipation, outcome processing, and social reward are not interchangeable. Threat/salience and cognitive-control findings are meaningful but more task-, state-, and method-dependent. Task-based evidence shows some convergence for threat-related amygdala reactivity, whereas regional structural brain correlates of childhood maltreatment are heterogeneous and developmentally conditional rather than spatially invariant. Direct same-sample longitudinal evidence establishing temporal ordering from trauma to immune change, neurocircuit alteration, and symptoms remains scarce. Peripheral biomarkers are not direct measures of central neuroinflammation, and current evidence does not support routine inflammatory testing or trauma-specific anti-inflammatory treatment. Peripheral inflammation is best understood as a context-dependent contributor in selected exposure and symptom profiles, rather than as a universal mediator, trauma-specific biomarker, or necessary explanation for all effects of childhood trauma. Future work requires prospective subtype-sensitive cohorts, repeated immune profiling, reliable circuit-sensitive tasks, multimodal imaging, and mechanism trials with prespecified safety and target-engagement endpoints.