Obsessive intrusive thoughts in nonclinical subjects. Part I. Content and relation with depressive, anxious and obsessional symptoms.

The present study reports on the development and preliminary validation of a 52 item self-report instrument designed to assess intrusive thoughts, images and impulses that are similar to the aggressive, sexual and disease-related thinking characteristic of clinical obsessions. Two hundred and ninety-three students completed the Obsessive Intrusions Inventory (OII) as well as standard self-report measures of negative cognitions and obsessive, anxious and depressive symptoms. Regression analysis revealed that intrusive thinking was a significant and unique predictor of obsessional but not anxious or depressive symptoms. Furthermore, intrusive thinking showed a moderate correlation with anxious but not depressive cognitions. The results indicate that the intrusive thoughts assessed by the OII are distinct from other forms of negative thinking and may, in fact, constitute an analogue form of clinical obsessions in nonclinical populations.