Questionnaire for Obsessive Compulsive Disorder Diagnosis (Q-OCDD): description and psychometric properties

This paper describes the Questionnaire for Obsessive-Compulsive Disorder Diagnosis (Q-OCDD)’ based on diagnostic criteria of DSM-IV. Decision criteria to classify a subject into one of three categories (OCD, Symptomatic, Asymptomatic) are described and two studies of some of its psychometric properties are shown in the non clinical and clinical group. Study 1 (non clinical group: 48 males and 190 females) determines: (a) agreement (k= 1) between two OCD inter-scorers, (b) convergent validity between Q-OCDD and Y-BOCS and MOCI. Convergent/divergent validity of Q-OCDD with Y-BOCS shows homogeneity in the Y-BOCS scores in the Asymptomatic and Symptomatic groups, there being a higher number of significant differences from the OCD group. Convergent validity of Q-OCDD with MOCI shows differences between the Asymptomatic and any one of the other two groups in all scales except in Slowness. Study 2 (clinical group: 11 males and 6 females) shows: (a) inter-scorer reliability (= 0.87), (b) convergent/divergent validity between Q-OCDD (with or without OCD) and Y-BOCS. There are statistically significant differences in the means of obsessions, compulsions and total between subjects with or without OCD, (c) the following values: sensitivity 78.6%, specificity 100.0%, and diagnostic efficiency 82.35% (From diagnoses established by clinical interview and Q-OCDD).