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

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.