Pavlovian Bias is Associated with Symptom Severity in Individuals with Anxious Depression

Human decision-making favors approach behavior to gain rewards and avoidance behavior to prevent punishment. While adaptive in some cases, this Pavlovian bias can also interfere with instrumental motivation, leading to suboptimal decisions. As maladaptive avoidance is a known maintenance factor in anxiety and depression, this could be especially relevant to individuals with these disorders. To assess whether Pavlovian bias is altered in this population, we examined 106 healthy comparisons (HCs), 88 individuals with depression (Dep), and 184 with comorbid anxiety and depression (AnxDep) using an Orthogonalized Go/No-Go Task. Participants’ choices and reaction times were modeled using a reinforcement learning and drift diffusion model (RL-DDM). As expected, results showed that accuracy was highest when Pavlovian and instrumental biases aligned and lowest when they conflicted. Linear models revealed no group differences in accuracy, reaction times, or any of the computational parameters. However, within the AnxDep group, Pavlovian bias was positively associated with depression severity and other affective symptoms, such as rumination and anxiety sensitivity. Consistent with this, levels of depression, rumination, and anxiety sensitivity in this group were each also negatively associated with accuracy on the task when approach actions were required to avoid punishment. These results suggest that Pavlovian bias may contribute to symptom severity within affective disorders by suppressing approach behaviors when they would be adaptive – potentially amplifying the avoidance behaviors known to maintain these disorders.