Reliability, Validity, and Clinical Utility of the Research Diagnostic Criteria for Temporomandibular Disorders Axis II Scales: Depression, Non-Specific Physical Symptoms, and Graded Chronic Pain

Aims: To analyze the reliability, validity, and clinical utility of the depression, non-specific physical symptoms, and graded chronic pain scales comprising the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II. Methods: Data resulting from independent longitudinal and cross-sectional epidemiological studies as well as randomized clinical trials conducted at the University of Washington and the University at Buffalo were submitted to descriptive, correlational, and inferential statistical analyses to evaluate selected psychometric properties of the RDC/TMD Axis II scales. Results: Analyses of available data from both TMD clinical centers revealed good to excellent reliability, validity, and clinical utility for the Axis II measures of depression, somatization, and graded chronic pain. Specifically, data were presented comparing the RDC/TMD depression scale to the Beck Depression Inventory and the Center for Epidemiologic Studies Depression Scale; these data supported concurrent validity of the RDC/TMD measure and its use as a depression screening tool. Its clinical utility lies in its demonstrated usefulness for alerting TMD clinicians to potentially noteworthy depressive symptomatology in TMD patients. Others have shown that elevated somatization, the tendency to report non-specific physical symptoms as noxious or troublesome, is a predictor of poor TMD treatment outcome. The present analyses demonstrated that the RDC/TMD Axis II non-specific physical symptoms scale has acceptable reliability and that severe levels of somatization can potentially confound interpretation of the Axis I clinical examination. The graded chronic pain scale was demonstrated to have clinical utility for tailoring TMD treatment to levels of a patient's psychosocial adaptation. Conclusion: The major RDC/TMD Axis II measures demonstrate psychometric properties suitable for comprehensive assessment and management of TMD patients. Keywords: temporomandibular disorders, depression, somatization, chronic pain, RDC/TMD, reliability, validity