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.

Validation of the Turkish Version of the Obsessive-Compulsive Inventory-Revised (OCI-R) in Clinical and Non-Clinical Samples

INTRODUCTION

The Obsessive-Compulsive Inventory-Revised (OCI-R) is a widely used self-report instrument developed to overcome the problems with the available instruments. The aim of this study was to assess the psychometric properties of the revised Obsessive Compulsive Inventory (OCI-R) in Turkish sample.

METHODS

The psychometric properties of the Turkish version of the Obsessive-Compulsive Inventory-Revised (OCI-R) were assessed in clinical samples (n=44 for patients with obsessive-compulsive disorder (OCD), and n=44 for patients with major depression (MD) and a non-clinical student sample (n=287).

RESULTS

The confirmatory factor analysis demonstrated that the original six-factor structure was valid in the Turkish sample. The overall and each of the subscales showed moderate to good internal consistency and convergent validity as well as test-retest reliability. However, the Cronbach's alpha was excessively low for the hoarding subscale in the OCD group. The total and subscale scores of the OCI-R satisfied at discriminating patients with OCD from both patients with MD and healthy controls, with an exception of the neutralizing subscale.

CONCLUSION

The Turkish version of the OCI-R did not reveal sound psychometric properties. Findings are discussed in the light of current theoretical considerations.