Delay discounting and nucleus accumbens functional connectivity are related to weight status in adolescents from the ABCD study.

Background: Despite the growing epidemic of paediatric obesity, questions remain regarding potential neural mechanisms for individual risk. Delay discounting is a cognitive process of comparison of valuation between immediate and delayed reward, which has been inconsistently linked to weight status. Moreover, central to the brain's reward system is the nucleus accumbens, a region structurally and functionally altered in obesity.

Objectives/methods: This study aimed to examine the relationships between two continuous metrics of weight status, performance on a monetary delay-discounting task and nucleus accumbens functional connectivity in 10-12-year-olds from the Adolescent Brain and Cognitive Development (ABCD) Study.

Results: Using multilevel longitudinal linear modelling, we found greater discounting was associated with higher BMI Z-scores (BMIz) and waist-to-height ratio Z-scores (WHtRz) (N = 3819). Moreover, we observed functional connectivity of the nucleus accumbens to the cingulo-opercular, dorsal attention, fronto-parietal, salience and ventral attention networks were predictive of BMIz (N = 1817). Nucleus accumbens functional connectivity was not found to mediate the association between delay-discounting behaviour and BMIz.

Conclusions: Delay discounting and nucleus accumbens functional connectivity are independently related to weight status in a large sample of early adolescents. A better understanding of the relationship between reward and overeating behaviours may better inform obesity interventions.