Abstract
Background: Interpersonal trauma is associated with a higher risk of developing symptoms of post-traumatic stress disorder (PTSD) following trauma exposure. PTSD, which is more prevalent among women, is characterised by heightened fear and difficulties regulating it. Although fear regulation deficits in PTSD are well documented, considerable variability exists in how individuals learn and regulate fear. Brain regions involved in fear learning and regulation follow distinct developmental trajectories and are more sensitive to stress at certain timepoints. As exposure to severe stress (e.g. trauma) could influence the development and/or functioning of brain regions involved in fear learning and regulation, the timing of such exposure may potentially induce differential effects.Objective: This study explores the association between the developmental period - childhood (0-11 years), adolescence (12-17 years), adulthood (18 years and older) - during which the first interpersonal trauma occurred, and fear learning and regulation processes in a sample of adult women.Methods: Ninety-five women with a history of interpersonal trauma reported their age at first exposure and underwent a validated two-day fear conditioning and extinction protocol (conditioning and extinction on one day, followed by extinction memory recall 24 h later). Skin conductance responses (SCR) were used to index physiological fear levels.Results: During fear conditioning and extinction, no group differences emerged. During the early phase of extinction memory recall, women whose first trauma occurred during adolescence or adulthood showed higher SCRs than those exposed during childhood (Time × Trauma age group: F(6, 2078.05) = 7.78, p < .001).Conclusion: These findings suggest that the developmental timing of trauma exposure influences fear regulation in adulthood, highlighting potential windows of vulnerability that could inform targeted interventions.