Aranovich-Risky Choice in OCD and Hoarding Disorder RUNNING TITLE: Risky Choice in OCD and Hoarding Disorder Dimensional Analysis of Decision Making Under Risk in Obsessive-Compulsive and Hoarding Disorders

Background: Many important decisions in life, such as consumption and savings decisions, involve risk. Attitudes towards risk are highly consequential in clinical disorders thought to be prone to “risky behavior”, such as substance use disorders, and those commonly associated with excessive risk aversion, such as obsessive-compulsive disorder (OCD) and hoarding disorder (HD). In this study, we investigated the risk preferences of participants with OCD and HD using a novel adaptive task and the prospect theory framework from behavioral economics. Methods: 39 participants with HD, 39 participants with OCD, and 38 healthy controls (HC) completed clinical assessments and an adaptive risky choice task. Risk aversion and probability weighting parameter values were estimated from choice data. Results: Participants with OCD and HD showed lower risk aversion than HC. The pattern of risk preferences was similar for OCD and HD and was characterized by an sshaped probability weighting function (PWF) that contrasted with the classic inverse-sshape PWF exhibited by HC. Best-fitting probability weighting parameters revealed statistically significant correlations with symptom scales: risk aversion was inversely correlated with depression, hoarding, and compulsion scores. Rationality of risk preferences was inversely correlated with hoarding severity and positively correlated with compulsion severity. Conclusions: Contrary to expectation, subjects with OCD and HD were less risk averse than HC. Hoarding (compulsion) scores were associated with lower (greater) rationality. Understanding how fundamental risk attitudes relate to specific psychopathology may contribute to our understanding of the cognitive manifestations of psychiatric illnesses and to the development of more precise and effective treatments. Aranovich-Risky Choice in OCD and Hoarding Disorder