Neural correlates of adverse childhood experiences, depression and chronic pain in the reward system

Adverse childhood experiences (ACEs) are common, altering behaviour and stress reactivity, with persistent structural and functional brain changes. ACEs are associated with a greater risk of physical and mental health morbidities, including depression and chronic pain (CP), which often co-exist. While changes in the reward system have been implicated in each condition, it remains unclear whether there are common neural mechanisms. Using brain scans from a large community sample, we examined how ACEs, depression, and CP affected the reward system. Individuals reporting both ACEs and CP exhibited reduced volume in the nucleus accumbens, a brain region associated with motivation and pleasure, particularly among women. Blunted reward-related activity in the basal ganglia was linked to higher depression scores, CP severity, and experiences of childhood sexual abuse. Importantly, these functional changes remained significant even after accounting for structural brain differences. Interestingly, brain structural-functional associations were weak, suggesting distinct underlying mechanisms. Structural brain alterations likely represent cumulative, enduring consequences of ACEs and CP, whereas altered reward activity appears more closely tied to current symptom severity. These findings reveal separable but converging neurobiological signatures of early adversity, pain, and depression within the brains reward system.