Objective:Obsessive-compulsive disorder is characterized by a chronic course that can vary between patients. The knowledge on the naturalistic long-term outcome of obsessive-compulsive disorder and its predictors is surprisingly limited. The present research was designed to identify clinical and psychosocial predictors of the long-term outcome of obsessive-compulsive disorder.Methods:We included 377 individuals with a current diagnosis of obsessive-compulsive disorder, who participated in the Netherlands Obsessive Compulsive Disorder Association study, a multicenter naturalistic cohort study. Predictors were measured at baseline using self-report questionnaires and clinical interviews. Outcome was assessed using the Yale-Brown Obsessive Compulsive Scale at 2-, 4- and 6-year follow-up.Results:The overall course of obsessive-compulsive disorder was characterized by two prominent trends: the first reflected an improvement in symptom severity, which was mitigated by the second, worsening trend in the long term. ...