Introduction: Cognitive features that play an important role in the development and maintenance of disordered gambling (DG) are impulsivity and sensitivity to reward. However, behavioural and neuroimaging findings are less consistent as one would expect when looking at the diagnostic criteria of the disorder. Given that almost half of the DGs suffer from comorbid depressive symptomatology our aim was to assess its impact on reward processing and response inhibition.
Methods: We presented two different tasks during 3 tesla functional magnetic resonance imaging to study the neurobiological correlates of 1) effort-related reward processing and 2) motor response inhibition (work in progress) in a large cohort of disordered gamblers (DGs) and healthy controls (HCs). Depressive symptoms were assessed using the Beck Depression Inventory (BDI). DGs and HCs were divided into subgroups (“high” and “low”) based on their BDI scores.
Results: Neither effort-related monetary reward processing nor inhibition-related brain activation differed between the complete groups of HCs and DGs. Notably, for both tasks we found a significant Group × BDI interaction. During receipt of monetary reward, DGs with higher BDI scores compared to DGs with lower BDI scores showed greater brain activity in the right insula cortex and dorsal striatum. No differences were observed for HCs with higher versus lower BDI scores. During successful response inhibition, DGs with higher BDI scores compared to those with lower scores revealed significantly diminished activity in a parieto-frontal network including inferior and middle frontal gyrus, anterior cingulate cortex, supplementary motor area and postcentral gyrus among other stopping-relevant regions. No differences were observed for HCs with higher versus lower BDI scores.
Conclusion: Comorbid depressive symptomatology in DGs has a significant impact on effort-related reward processing and inhibition-related brain activation. Our findings strengthen the need for subgroup comparisons in future investigations of disordered gambling as part of a personalized medicine approach.