OCD Compulsions as Aberrant Integration of Uncertainty from Local Goals to Global Goals.

Recent years have seen unprecedented increases in compulsive behaviors, even in previously undiagnosed populations. Yet, despite their rising prevalence and the fact that compulsions-notably associated with obsessive-compulsive disorder (OCD), but also a key feature of other disorders such a hoarding or body dysmorphic disorder-significantly hamper daily function, the specific mechanisms of their formation remain unknown. Previous research holds mixed findings on compulsivity-linked cognitive deficits, and, while many accounts assume that compulsions aim to reduce anxiety, most individuals with anxiety do not develop compulsions-suggesting that the anxiety-reduction account is incomplete. We propose here a broader, uncertainty-resolving account of compulsivity, that bypasses the commonly-used, single-goal structure of many cognitive tasks to leverage the real-world hierarchical structure of goals-with "local", short-term subgoals (e.g., "how do I clean my hands?") in the service of long-term, "global" goals ("how do I stay healthy?"). In that framework, we suggest that compulsivity may reflect a deficit in integrating uncertainty from local to global goals, which still spares the basic circuitry of reward and learning. We tested 20 OCD patients and 20 healthy volunteers in a predictive inference task with a hierarchical structure of local uncertainty reduction in the service of global uncertainty reduction. Both groups learned the reward structure of the local environment based on observed data; however, only the healthy volunteers showed evidence of integrating learned knowledge at the local level to reduce uncertainty about the higher level of the task hierarchy. This indicates a potential mechanism for compulsions that relies on the inability to adaptively integrate, prioritize, and "toggle" among different local goals in the service of global goals.