The significance of obsessions

The purpose of this thesis was to investigate a specific cognitive theory of obsessions; namely, that unwanted and repugnant intrusive thoughts cause distress and persist when the person interprets their occurrence as highly personally significant and important. Two studies were conducted. In the first study, we described the development and undertook a validation study of a new scale of obsessional-compulsive symptoms, the Vancouver Obsessional Compulsive Inventory (VOCI). This measure was a necessary first step because established measures of obsessional-compulsive symptoms are inadequate in their assessment of a number of domains of obsessional-compulsive complaints, particularly obsessions. Our findings in samples of people with obsessivecompulsive disorder (OCD), people with other anxiety disorders or depression, community adults, and undergraduate students suggest that the VOCI is a promising new measure. In the second study, we investigated the role of interpretations of the personal significance and importance of intrusive thoughts in the occurrence of obsessions. Specifically, we hypothesized that people who have repugnant obsessions or frequent, distressing intrusive thoughts would interpret their intrusive thoughts as highly personally significant and important. Our hypotheses were, in general, supported. There was a clear relationship between beliefs and interpretations of the importance of thoughts and obsessions in both OCD and nonclinical samples. In addition, these beliefs and appraisals appeared to be specifically related to repugnant obsessions, rather than obsessive-compulsive complaints in general. This research represents one of the first attempts to evaluate the assertion that misinterpretations of intrusive thoughts are fundamental in the experience of obsessions. The development of the VOCI was a necessary first step in evaluating the relationship between interpretations of personal significance and particular obsessional-compulsive complaints. By demonstrating specific interpretations that are associated with clinical obsessions, we hope to refine cognitive-behavioural models of obsessions, and suggest ways in which current cognitive-behaviour therapy for obsessions can be sharpened and made more effective.Arts, Faculty ofPsychology, Department ofGraduat