Psychosocial and demographic correlates of temporomandibular disorders and related symptoms: An assessment of community and clinical findings

This study investigated the factor structure and relative prevalence of temporomandibular disorder (TMD) symptoms, in relation to demographic and psychosocial variables in a community sample. Two empirically distinct clusters of TMD symptoms were identified. Similar to reports of TMD clinic patients, more symptoms were reported by females than males and the greatest symptom prevalence was found in subjects between the ages of 30 and 49 years. Further, the number of symptoms reported was significantly and linearly related to scores on depression and repression-sensitization scales. These relationships, however, were similar for both sets of symptom composites even though one composite is clearly identifiable as the core TMD symptoms and the second composite consists of peripheral symptoms. Since the two symptom composites share some common variance, the relationship between demographic and psychosocial characteristics and the number of composite I and composite II symptoms was examined while controlling for the presence of symptoms from the other composite. When controlling for the presence of composite II symptoms, the correlations between psychosocial and demographic characteristics and composite I symptoms are small. When the presence of composite I symptoms is controlled there is little change in the magnitude of the correlations between psychosocial and demographic characteristics and composite II symptoms. It is concluded that the psychosocial profile described in clinical research is actually more characteristic of individuals with pain/dysfunction symptoms other than the classic TMD symptoms and that the relationship between core TMD symptoms (composite I) is largely spurious. It is suggested that this psychosocial profile of TMD patients may have developed through associating certain psychosocial characteristics with TMD while such characteristics are actually present in TMD clinic patients because of the covariation of the two symptom composites in individuals seeking treatment in TMD clinics.