The overvalued ideas scale: development, reliability and validity in obsessive-compulsive disorder

The presence of overvalued ideas in obsessive-compulsive disorder (OCD) has , been theoretically linked to poorer treatment outcome [Kozak, M. J. & Foa , E. B. (1994). Obsessions, overvalued ideas and delusions in obsessive-com pulsive disorder. Behaviour Research and Therapy, 32, 343-353]. To date, no measures have been developed which quantitatively assess levels of overval ued ideas in obsessive-compulsives. The present studies examined the psycho metric properties of a scale developed to measure this form of psychopathol ogy, the Overvalued Ideas Scale (OVIS). In study 1, 102 patients diagnosed with OCD were administered a battery of instruments including the OVIS at b aseline and two weeks later, prior to initiating treatment. Results indicat e that the OVIS has adequate internal consistency reliability (coefficient alpha = 0.88 at baseline), test-retest reliability (1 = 0.86) and interrate r reliability (r = 0.88), Moderate to high levels of convergent validity wa s found with measures of obsessive-compulsive symptoms, a single item asses sment of overvalued ideas and psychotic symptoms. Medium levels of discrimi nant validity with measures of anxiety and depression was obtained in this study. Individuals determined to have high OVI showed greater stability of this: pathology than those with lower OVI, suggesting that overvalued ideas are stable for extreme scorers. In study 2 a total of 40 patients particip ated who were diagnosed with OCD. The same battery of instruments was admin istered as in study 1, as well as the Beck Depression Inventory and Beck An xiety Inventories. Results were similar to that obtained in study , includi ng a relative lack of discriminant validity with self-report measures of de pression and anxiety. It is suggested that further research with the OVIS m ay show predictive value in treatment outcome studies of OCD. (C) 1999 Else vier Science Ltd. All rights reserved.