Modelling Effort-based Decision-making: A Dimensional Approach to Understanding Motivation Deficits in Schizophrenia and Major Depressive Disorder

Motivation deficits are prominent symptoms in schizophrenia (SZ) and major depressive disorder (MDD). One critical facet of motivation is effort valuation and decision-making, whereby cost-benefit calculations guide the amount of effort one is willing to expend for a desired reward. In order to advance our understanding of how individuals with SZ and MDD utilize different sources of cost-benefit information to guide choice behaviour, the present study utilized a dimensional approach to characterize individual differences in the computations underlying effort-based decision-making. A sample of 145 participants (n=51 SZ, n=43 MDD, n=51 healthy controls (HC)) completed the Effort Expenditure for Rewards Task (EEfRT), with mixed effects modelling conducted to estimate the subject-specific predictors of decision-making. Our findings revealed meaningful individual differences amongst participants in their utilization of cost-benefit information. Further, two clusters of individuals were identified, irrespective of diagnostic status, with distinct behavioural profiles of cost-benefit information utilization and differential clinical correlates.M.A