Reward dysfunction represents a key feature of addiction progression. Although anxiety symptoms are a core feature of obsessive–compulsive disorder (OCD), current literature shows growing evidences of a reward dysfunction in OCD, mainly in resistant patients. These data support the hypothesis that addiction and OCD share some common neurobiological dysfunctions and corroborate the idea that OCD starts as an anxiety disorder and becomes a behavioral addiction through the same stages of addiction. A common link between all substance abuse and the addictive behaviors is their rewarding effect. Compulsion is a suffering reducing activity that might step on the border of rewarding experience due to its capacity to reduce anxiety and distress generated by obsessions. In this perspective compulsion could be potentially addictive. In fact, many patients report having a sort of’addiction to compulsions’. From this perspective, it is possible to conceptualize OCD progression as a slow progression to a’compulsions addiction’. In this view, it is also possible to hypothesize a clinical staging of OCD consisting of three main stages. First stage: the endophenotype stage. In this stage the patient present only subtreshold symptoms, but show endophenotypical abnormalities such as motor disinhibition and cognitive inflexibility. Second stage: the alarm stage. In this stage the patient has the OCD onset and the anxiety dimension is prominent. Third stage: the reward dysfunction stage. In this stage the patient becomes addicted to compulsions.