Reward dysregulation following early- life adversity: pathways to externalising behaviours

Early-life adversity (ELA) has long-lasting effects on physical and mental health, as itimpairs the neurodevelopment of crucial pathways such as the reward-related circuitry. Currentevidence has predominantly linked ELA to blunted reward sensitivity and internalisingdisorders, yet empirical work has also identified reward hypersensitivity, and either can alsobe linked to externalising disorders. This systematic review assesses the relevant literature onELA, dysregulated reward processes, and externalising symptoms. Literature screeningidentified 34 relevant papers, 24 of which support either a hypersensitivity to reward (n = 12)or a hyposensitivity (n = 12) to reward, associated with externalising behaviours in individualswith a history of ELA. Additionally, the reviewed studies and tasks assess reward processesalongside affective regulation, supporting its role in shaping reward-related responses. Wepropose a broader affective-related reward dysregulation to reconcile the conflicting evidence:reward sensitivity may depend on current and general affective state and regulation, mouldedby ELA experiences. Further empirical studies should test this hypothesis, contributing to boththeoretical models and clinical frameworks for more targeted therapeutic approaches to trauma-and mood-related disorders.