Specificity and structure of obsessive-compulsive disorder symptoms.

Research in obsessive-compulsive disorder (OCD) shows heterogeneous symptoms. No longer satisfied with categorizations of obsessions or compulsions, contemporary symptom measures are multidimensional and assess specific symptoms (e.g., checking, washing) as well as experiences bearing a putative relation to OCD (e.g., hoarding). This two-study correlational design examined three OCD measures in student samples (total N=805). Objectives were to evaluate (a) the measures' joint factor structure; (b) specificity of relations between OCD and symptoms of general distress, panic, and depression; and (c) the pattern of convergent and discriminant relations among OCD scales after accounting for general distress. Results were that both exploratory and confirmatory factor analyses supported a five-factor structure: checking, contamination, rituals, impulses, and hoarding. Scales showed meaningful patterns of relations with general distress, panic, and depression. That is, OCD symptoms correlated moderately with general distress and panic, but related more weakly to depression. Parallel scales measuring the five domains were reliable and showed strong convergence across instruments. After accounting for general distress, discriminant validity was found: Mono-trait correlations between instruments were the highest correlations overall and were substantially higher than hetero-trait values either within or between instruments. We discuss the importance of understanding relations among OCD measures, between OCD and other symptoms, and implications of this type of analysis for defining OCD. Copyright 2007 Wiley-Liss, Inc.