Objectives: The relationship between the rate of chronic pain-related disability and depression and somatization levels as well as the influence of pain duration on Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis II findings were assessed in a three centre investigation.
Methods: The study sample (N=1149; F:M 4.1:1, m.a. 38.6 years) consisted of patients seeking for TMD treatment and undergoing RDC/TMD axis II psychosocial assessment to be rated in chronic pain-related disability (Graded Chronic Pain Scale, GCPS), depression (Symptoms Checklist-90[SCL-90] scale for depression, DEP) and somatization levels (SCL-90 scale for non-specific physical symptoms, SOM). The null hypotheses to be tested were that (1) no correlation existed between GCPS categories and DEP and SOM scores, and (2) no differences emerged between patients with pain from more or less than 6 months as for the prevalence of the different degrees of pain-related impairment, depression, and somatization.
Results: In the overall sample, the prevalence of high pain-related disability (GCPS grades III or IV), severe depression and somatization was 16.9%, 21.4%, and 28.5%, respectively. A correlation was shown between GCPS and both DEP and SOM categories (Spearman's correlation test, p<0.001). A significant association between pain lasting from more than 6 months and high GCPS scores was shown (chi(2), p<0.001), while no association was found between DEP and SOM scores and pain duration in the overall sample (chi(2), p=0.742 and p=0.364, respectively).
Conclusions: Pain-related disability was found to be strongly related with depression and somatization levels as well as associated with pain duration. Depression and somatization scores were not associated with pain duration.
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