Revision of the Padua Inventory of obsessive compulsive disorder symptoms: distinctions between worry, obsessions, and compulsions.

The Padua Inventory (PI), a self-report measure of obsessive and compulsive symptoms, is increasingly used in obsessive compulsive disorder (OCD) research. Freeston, Ladouceur, Rheaume, Letarte, Gagnon and Thibodeau (1994) [Behaviour Research and Therapy, 32, 29-36], however, recently showed that the PI measures worry in addition to obsessions. In an attempt to solve this measurement problem, this study used a content distinction between obsessions and worry to revise the PI. The revision was constructed to measure five content dimensions relevant to OCD i.e. (1) obsessional thoughts about harm to oneself or others; (2) obsessional impulses to harm oneself or others; (3) contamination obsessions and washing compulsions; (4) checking compulsions; and (5) dressing/grooming compulsions. A total of 5010 individuals participated in the study, 2970 individuals completing the PI and the Penn State Worry Questionnaire (PSWQ) and an additional 2040 individuals completing only the PI. The results provided support for the reliability and validity of the revision. In addition, the revision of the PI was more independent of worry, as measured by the PSWQ, than the original PI. Support was thus found for the validity of the content distinction between obsessions and worry. The importance of this content distinction is also discussed for the evaluation of other hypothesized distinctions between obsessions and worry.

The utilization of nonpatient samples in the study of obsessive compulsive disorder.

Obsessive compulsive disorder (OCD) is increasingly studied in nonpatients, primarily through the selection of individuals who score high on a self-report measure of OCD. The usefulness of this methodology for understanding OCD presupposes that some of the individuals in the high-scoring group meet diagnostic criteria for OCD, that the obsessive-compulsive behaviors in the high-scoring individuals are stable across time to a certain degree, and that the features associated with OCD in patients also are found in the high-scoring nonpatients. Two studies are reported which provide support for these three assumptions. Together the studies suggest that OCD can be productively examined by the selection of individuals who score high on a self-report measure of OCD. Cautions in the use of this methodology for the study of OCD are also noted.