Psychological distress and diagnostic subgroups of temporomandibular disorder patients.

This study examined the nature and extent of psychological differences among diagnostic subgroups of temporomandibular disorder (TMD) patients. Three subgroups were identified and labeled as: (1) primary myalgia, (2) primary temporomandibular joint (TMJ) problems, or (3) combination myalgia and TMJ problems. Patients' (n = 112) levels of pain and distress were measured using a VAS pain scale, the McGill Pain Questionnaire, the Beck Depression Inventory, the State-Trait Anxiety Scale and the MMPI. Patients with primary myalgia had the highest scores on the pain and distress measures while patients in the combination group scored between the myalgia and TMJ problem subgroups. When differences in pain levels were controlled, the differences among groups on measures of anxiety and depression were attenuated while the differences on measures of somatic overconcern remained significant. Discriminant function analysis using psychological variables to predict diagnostic grouping produced correct identification of 74% of the structural patients and 46% of the myalgia patients. Implications for different etiological factors among the 3 groups are discussed.