Decision making in OCD and its interaction with metacognition and genetics: A proposal towards expected value of control theory

Obsessive – Compulsive Disorder is a neurocognitive disorder which affects approximately 3% of the general population. Almost 33% of patients with OCD diagnosis remain treatment refractory even after the prescription of pharmacological options we have. Thus, we need more comprehensive understanding of the neurobiological basis of OCD to propose more effective treatment options. One of the remarkable characteristics of OCD is the accompanying insight about the symptoms. The patients with OCD diagnosis acknowledge that there is no need to wash their hands repeatedly in the case of contamination obsession, however they can not abstain from performing this compulsive behavior. In this dissertation, the mechanism behind this discrepancy was tried to be understood. The perceptual decision making characteristics of the patients with OCD diagnosis is scarcely studied area of research. This dissertation focused on perceptual decision making in healthy participants with varying degrees of propensity to OCD. In the first study, the relation between dopamine gene related gene polymorphisms (COMT, DRD2 and DARPP-32) and latent decision making variables in addition to obsessivecompulsive factors. The results of this study suggest that having Met/Met allele of COMT gene is associated with lower decision threshold, higher drift rate and higher obsessivecompulsive factor scores. In the second study, metacognitive assessments of participants, in addition to perceptual decision making task, were collected. This study showed that participants with high propensity to OCD have more efficient metacognitive assessments, however they can not use this metacognitive information to modulate the strategy used in their subsequent action in decision making task. Lastly, current literature about cognitive alterations observed in OCD was reviewed in the framework of Expected Value of Control (EVC) Theory which proposes a computational model and neuronal allocations for the adjustment of cognitive control. Overall, these results suggest that participants with high propensity to OCD struggles in behavioral adaptation and this might be the result of a dysfunction in different parts of EVC. Keywords: OCD, decision making, COMT gene, metacognition, Expected Value of Control Theory