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Development and Psychometric Properties of the Dimensional Obsessive-Compulsive Scale (DOCS). Jonathan S. Abramowitz, PhD University of North Carolina at Chapel Hill. Collaborators. Brett Deacon Bunmi Olatunji Michael Wheaton Noah Berman Diane Losardo Kiara Timpano.
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Development and Psychometric Properties of the Dimensional Obsessive-Compulsive Scale (DOCS) Jonathan S. Abramowitz, PhD University of North Carolina at Chapel Hill
Collaborators • Brett Deacon • Bunmi Olatunji • Michael Wheaton • Noah Berman • Diane Losardo • Kiara Timpano • Patrick McGrath • Bradley Riemann • Thomas Adams • Throstur Bjorgvinsson • Eric Storch • Lisa Hale
Assessment of OCD • OCD is heterogeneous • Challenges in assessing OCD symptoms • Measure a wide range of possible symptoms • Do so efficiency (as few items as possible) • Approaches • Assess only the quintessentialobs. and comps. • PI/PI-R, OCI/OCI-R, MOCI • Assess the severity of the patient’s main symptoms • YBOCS/D-YBOCS
Limitations of Existing OCD Measures • Symptom severity is confounded with breadth • Severity is confounded with popularity of sx • One dimensional assessment of severity • Obsessions assessed separately from rituals • Avoidance? • Hoarding?
We Need New OCD Measures • Assess the severity of empirically supported symptom dimensions • Contamination, responsibility for harm/mistakes, Unacceptable thoughts, symmetry/incompleteness • Multiple severity parameters • Assess avoidance • Assess severity independent of type or range of symptoms • Easy to administer
DOCS • Four sections (one for each symptom dimension) • Contamination, responsibility, unacceptable thoughts, symmetry/incompleteness • Each section contains • Examples of obsessions, compulsions, avoidance • Five severity questions (time, avoidance, distress, interference, control) rated 0 to 4 • 20 items in all Approximately 5-10 mins. to read and complete
Study Aims • Factor structure • Reliability and Validity • Diagnostic accuracy • Treatment sensitivity
Method • Participants (data collected at 8 sites) • 315 adults with OCD • 198 adults with other anxiety disorders (OAD) • 1,044 unselected undergraduate students • Measures
Results: Exploratory Factor Analysis with Half of the Student Sample
Results: Confirmatory Factor Analyses • Goodness-of-fit parameters indicated that the student and clinical data fit the four-factor structure very well.
Correlations among factors showing weak to moderate relationships
Reliability • Cronbach’salpha and item-total correlation • Test-retest
Convergent and Discriminant Validity: DOCS Factors/Subscales
Diagnostic Accuracy: ROC Analyses • DOCS total score discriminates: • OCD patients from nonclinicals (AUC = .86) • OCD patients from OAD patients (AUC = .77) • Cutoff scores • A score of 21 correctly classified 70% of OCD patients and 70% of OAD patients • A score of 18 correctly classified 78% of OCD patients and 78% of students
Diagnostic Accuracy: DOCS vs. OCI-R OCD vs. Nonclinical OCD vs. OAD • Diff in AUC = .06; Z = 4.68, p < .01 Diff in AUC = .08; Z = 3.57, p < .01
Conclusions • The DOCS is a conceptually & psychometrically sound measure of OC symptoms in patients and nonpatients • Addresses many of the limitations of existing measures • Uses • Baseline assessment of symptom dimensions • Treatment response (use “main” symptom dimension) • Measure of psychopathology for research • Future work • Test-retest in a clinical (OCD) group • Child version • Translations