Obsessive-Compulsive Disorder is part of the Anxiety Disorders spectrum. It is a more severe manifestation of a concern, a fear, or a preoccupation with something physical or psychological, or with a relationship, whose symptoms rise to the level of pathology. What makes it pathological is the severity of the symptoms, i.e. the persistence and intrusiveness of the obsessions, and the frequency and intensity of the compulsions. It is not a disorder that will disappear by itself if left untreated.  If you or someone you love appear to suffer from OCD, it will be necessary to confirm the diagnosis through specific testing and a diagnostic interview, and then seek treatment with a recommended approach such as CBT (possibly combined with medication.)