Cap. 9

Obsessive-compulsive disorder (OCD) is, as its name implies, characterized by obsessions (i.e., recurrent thoughts or images, particularly ones that cause distress) as well as compulsions (i.e., urges to perform mental or physical acts repeatedly), both of which significantly impair everyday functioning [1]. Obsessions are considered to be recurrent distressing impressions that something is wrong with an action or with a situation, such as an error or an imminent danger [2–4]. Compulsions are generally conceptualized as aiming to prevent feared harmful events and are thus associated with an increased sense of responsibility [5, 6]. However, they may also be motivated by particular sensory experiences concerning actions, such as feelings of incompleteness, that trigger the need to adjust them, rather than the avoidance of potential harm [7]. Both the sense of responsibility and the feeling of incompleteness can be viewed as experiences of actions that are obviously in conflict with the actual action context. Specifically, compulsions can be seen as behavioral responses to recurrent feelings of dissatisfaction regarding an intended achievement. Moreover, OCD features have been consistently connected to deficits affecting action processing, such as action planning [8, 9] and action monitoring [10, 11]. Research on the sense of agency has highlighted the importance of action specification (e.g., outcome anticipation) and action monitoring (e.g., assessing the degree of concordance between anticipated and actual outcomes) in the subjective understanding of “what one is doing” and “what one is causing” [12–17]. Hence, a dysfunction affecting these components of action processing could lead to an incon-