The Toronto Obsessive-Compulsive Scale: Psychometrics of a Dimensional Measure of Obsessive-Compulsive Traits

Abstract Objective To describe the Toronto Obsessive-Compulsive Scale (TOCS), a novel 21-item parent- or self-report questionnaire that covers wide variation in obsessive-compulsive (OC) traits, and to evaluate its psychometric properties in a community-based pediatric sample. Method The TOCS was completed for 16,718 children and adolescents between the ages of 6 and 17 years in a community setting. We assessed internal consistency, divergent and convergent validity with the Obsessive-Compulsive Scale of the Child Behavior Checklist (CBCL-OCS) and the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Rating Scale (SWAN) attention-deficit/hyperactivity disorder (ADHD) rating scales, inter-rater reliability, and sensitivity and specificity. Results The internal consistency of the 21 TOCS items was excellent (Cronbach’s α=0.94). TOCS was moderately correlated with the CBCL-OCS (Spearman correlation=0.51) and poorly correlated with the SWAN (Pearson correlation=0.02). Sensitivity and specificity analyses indicated that the TOCS total score of greater than 0 successfully discriminated community-reported cases from non-cases. OC traits were continuously distributed both at the total score and dimensional level in our pediatric community sample. Conclusion TOCS is a multidimensional measure of OC traits in children and adolescents with sound psychometric properties. TOCS reveals that OC traits are common and continuously distributed in a community sample. TOCS may be a useful measure for studies of the characteristics and etiology of OC traits.