According to the cognitive model, Obsessive-compulsive disorder (OCD) is maintained by various belief factors such as an inflated sense of responsibility, perfectionism and an overestimation about the importance of thoughts. Despite much support for this hypothesis, there is a lack of understanding about the role of self-concept in the maintenance or treatment of OCD. Guidano and Liotti (1983) suggest that individuals who are ambivalent about their self-worth, personal morality and lovability use perfectionistic and obsessive compulsive behaviours to continuously restore self-esteem. This thesis develops a model of OCD that integrates self-ambivalence in the cognitive model of OCD. (For complete abstract open document)