Factor structure and temporal stability of the Vancouver Obsessional Compulsive Inventory–Mental Contamination Scale (VOCI-MC) and psychometric properties of its Italian version

Abstract

ObjectiveThe Vancouver Obsessional Compulsive Inventory–Mental Contamination Scale (VOCI-MC) is a self-report instrument that assesses symptoms of mental contamination. The aim of this study was to investigate the psychometric properties of the Italian version of the VOCI-MC in non-clinical and clinical samples. MethodFactor structure, internal consistency, temporal stability, construct and criterion validity were investigated in 541 participants from the general population, 120 participants diagnosed with OCD and 31 participants diagnosed with other anxiety disorders (OAD). For some of these analyses, our OCD sample was subdivided into those with contamination-related symptoms and concerns (n=39) and those whose OCD excluded concerns related to contamination fear (n=81). Exploratory and confirmatory factor analyses supported the expected one-factor structure of the VOCI-MC both in non-clinical and OCD sample. ResultsVOCI-MC scores showed good internal consistency, temporal stability, construct validity and criterion validity. In particular, the VOCI-MC successfully discriminated between those with OCD who reported contamination-related concerns and all other groups of participants. ConclusionThese findings suggest that the Italian version of the VOCI-MC retains the adequate psychometric properties of the original, provide preliminary evidence of its one-factor structure and temporal stability, and suggest that it can be confidently used as an assessment tool of mental contamination symptoms in both clinical and research settings.