Goal-directed and habitual decision making under stress in Gambling Disorder: an fMRI study

The development of addictive behaviors has been suggested to be related to a transition from goal-directed to habitual decision making. Stress is a factor known to prompt habitual behavior and to increase the risk for addiction and relapse. In the current study, we therefore used functional MRI to investigate the balance between goal-directed ‘model-based’ and habitual ‘model-free’ control systems and whether acute stress would differentially shift this balance in gambling disorder (GD) patients compared to healthy controls (HCs). Using a within-subject design, 22 patients with GD and 20 HCs underwent stress induction or a control condition before performing a multistep decision-making task during fMRI. Salivary cortisol levels showed that the stress induction was successful. Contrary to our hypothesis, GD patients showed intact goal-directed decision making, which remained similar to HCs after stress induction. Bayes factors provided substantial evidence against a difference between the groups or a group-by-stress interaction on the balance between model-based and model-free decision making. Similarly, neural estimates did not differ between groups and conditions. These results challenge the notion that GD is related to an increased reliance on habitual (or decreased goal-directed) control, even during stress.