Cognitive dynamics of intertemporal choice in gambling disorder.

Gambling Disorder (GD) is a behavioral addiction characterized by the persistence of recurrent gambling behaviors despite serious adverse consequences. One of the key features of GD is a marked inability to delay gratification and an overall impairment of decision-making mechanisms. Indeed, in intertemporal choice (ITC) tasks, GD patients usually display a marked tendency to prefer smaller-sooner over larger-later rewards (temporal discounting, TD). However, ITC represents a highly verbal/explicit measure, and as such it might not be sensitive to implicit decision biases. Here we sought to uncover the implicit mechanisms underlying the ITC impairment in GD by employing the process-tracing method of mouse kinematics. To this aim, we collected and analyzed ITCs and kinematics measures from 24 GD patients and 23 matched healthy control participants (HC). In line with the relevant literature, the results showed that GD patients discounted future rewards more steeply compared to HCs. Additionally, the results of kinematics analyses showed that patients were characterized by a strong bias toward the immediate option, which was associated with straight-line trajectories. Conversely, the delayed option was selected with edge-curved trajectories, indicating a bias toward the immediate option which was revised in later stages of processing. Interestingly, kinematics indices were also found to be predictive of individual discounting preferences (i.e., discount rates) across the two groups. Taken together, these results suggest that kinematics indices, by revealing hidden and implicit patterns of attraction toward the unselected choice option, may represent reliable behavioral markers of TD in gambling disorder.