Controversies in the aetiology of temporomandibular disorders. Part 1. Temporomandibular disorders: all in the mind?

The aetiology of temporomandibular disorders (TMDs) is now considered to be multifactorial but the relative importance of individual aetiological factors is still controversial. Psychosocial factors play an important role in the aetiology of TMDs, in adaptation to pain and eventual recovery. TMD patients exhibit a variety of psychological and behavioural characteristics including increased somatization, stress, anxiety and depression. Subcategorisation of TMD patients into joint-related and muscle-related groups reveals psychological differences. Myogenic patients have increased severity of pain and suffer enhanced psychological distress. Within this group of patients are a minority of refractory cases who show marked overlap with those suffering from chronic pain syndrome; such patients benefit from psychiatric assessment and treatment. However, no common TMD personality profile has emerged from the psychometric test research. Recent knowledge of the molecular pathways induced by stress and the evaluation of stress-response substances may, in the future, provide diagnostically valuable biochemical markers of disease susceptibility. The role of psychological factors in the development of TMDs in the general population is critically examined.