Neurobehavioural mechanisms of threat generalization moderate the link between childhood maltreatment and psychopathology in emerging adulthood

Background: Childhood maltreatment is a transdiagnostic risk factor for later psychopathology and has been associated with altered brain circuitry involved in the processing of threat and safety. Examining threat generalization mechanisms in young adults with childhood maltreatment and psychiatric symptoms may elucidate a pathway linking early-life adversities to the presence of subclinical psychopathology. Methods: We recruited youth aged 16­25 years with subclinical psychiatric symptomatology and healthy controls. They were dichotomized into 2 groups: 1 with a high level of childhood maltreatment (n = 58) and 1 with no or a low level of childhood maltreatment (n = 55). Participants underwent a functional MRI threat generalization paradigm, measuring self-reported fear, expectancy of an unconditioned stimulus (US) and neural responses. Results: We observed interactions between childhood maltreatment and threat generalization indices on subclinical symptom load. In individuals reporting high levels of childhood maltreatment, enhanced generalization in self-reported fear and US expectancy was related to higher levels of psychopathology. Imaging results revealed that in the group with high levels of childhood maltreatment, lower activation in the left hippocampus during threat generalization was associated with a higher symptom load. Associations between threat generalization and psychopathology were nonsignificant overall in the group with no or low levels of childhood maltreatment. Limitations: The data were acquired in a cross-sectional manner, precluding definitive insight into the causality of childhood maltreatment, threat generalization and psychopathology. Conclusion: Our results suggest that threat generalization mechanisms may moderate the link between childhood maltreatment and subclinical psychopathology during emerging adulthood. Threat generalization could represent a vulnerability factor for developing later psychopathology in individuals being exposed to childhood maltreatment.