Development of a Psychometric Instrument Based on the Inference-Based Approach To Obsessive-Compulsive Disorder: the Obsessional Probabilistic Inference Scale

Abstract

Introduction: The current article addresses the validation of the construct of obsessional probabilistic inference in clinical and non-clinical samples. Obsessional probabilistic inference or obsessional doubt refers to a type of inferential process resulting in the belief that a state of affairs "maybe" causes development of a maladaptive cognitive coping style in terms of obsessing. Methods: The latent structure of the Obsessional Probabilistic Inference Scale (OPIS) was evaluated with confirmatory factor analysis. Results: Explanatory and confirmatory factor analyses indicated that a one-factor solution was satisfactory for the instrument, assessing a unidimensional psychological construct. The OPIS was shown to have high internal consistency in all samples, as well as temporal stability, relying on predominantly non-clinical individuals. The scale exhibited high convergent validity and successfully discriminated patients with obsessive-compulsive disorder from both depressive patients and controls. Conclusion: The findings replicated and extended the role of reasoning process in the development and maintenance of obsessive compulsive symptoms. The results are discussed in regard to assumptions of the inference-based approach to obsessive-compulsive disorder.