Description

The Vancouver Obsessional Compulsive Inventory (VOCI-55) is a psychometric instrument designed to assess the severity and range of symptoms associated with Obsessive-Compulsive Disorder (OCD). The questionnaire consists of 55 items that evaluate different obsessive thoughts and compulsive behaviours related to OCD.

The VOCI-55 assesses six main dimensions of obsessive-compulsive symptoms, including contamination, checking, obsessions, symmetry/ordering, hoarding, and neutralizing unwanted thoughts.

Objective

The main objective of the VOCI-55 is to provide a detailed assessment of OCD symptoms, allowing clinicians and researchers to identify specific patterns of obsessions and compulsions and determine the severity of symptoms.

The instrument can also support the design, evaluation, and monitoring of therapeutic interventions, including psychological and pharmacological treatments.

Structure and Content

The VOCI-55 evaluates multiple dimensions of obsessive-compulsive symptomatology.

The Contamination dimension assesses fears related to contamination and excessive cleaning behaviours. The Checking dimension evaluates repetitive checking behaviours, such as repeatedly verifying whether actions or situations have been completed correctly.

The Obsessions dimension examines intrusive and repetitive thoughts related to danger, harm, or unwanted events. The Symmetry/Ordering dimension evaluates the need for order, symmetry, and arranging objects in a specific manner.

The Hoarding dimension assesses difficulties in discarding objects and excessive accumulation behaviours, while the Neutralizing dimension focuses on unwanted thoughts, including concerns related to morality or inappropriate ideas.

Scoring Method

Each item of the VOCI-55 is rated using a Likert-type scale, with participants evaluating the frequency and intensity of their obsessive thoughts and compulsive behaviours.

Scores can be calculated for each individual dimension as well as for the overall scale. Higher scores indicate greater severity and frequency of obsessive-compulsive symptoms.

Data Analysis and Use

Data obtained from the VOCI-55 are used to examine the spectrum and severity of OCD symptoms in individuals. Statistical analyses include reliability testing, such as Cronbach’s alpha, to evaluate the internal consistency of the items within each subscale.

Factor analysis is used to confirm the underlying structure of the dimensions measured by the questionnaire, while correlation analysis can examine relationships between OCD symptoms and other psychological factors, such as anxiety and depression.

The VOCI-55 can be used in clinical studies to assess OCD severity, monitor treatment progress, and support the development of individualized therapeutic approaches.

Validity and Reliability

The calibration and psychometric evaluation of the VOCI-55 include reliability analysis to determine whether the subscales consistently measure OCD symptoms, factor analysis to confirm the six-dimensional structure of the questionnaire, and cross-validation studies in different populations to ensure validity and reliability.

References

Thordarson, D. S., Radomsky, A. S., Rachman, S., Shafran, R., Sawchuk, C. N., & Hakstian, A. R. (2004). The Vancouver Obsessional Compulsive Inventory (VOCI). Behaviour Research and Therapy, 42(11), 1289–1314.

Radomsky, A. S., Thordarson, D. S., & Rachman, S. (2006). The Vancouver Obsessional Compulsive Inventory (VOCI): Further validation in a clinical sample. Behaviour Research and Therapy, 44(1), 123–136.

Rachman, S. (1997). A cognitive theory of obsessions. Behaviour Research and Therapy, 35(9), 793–802.