Temporomandibular disorders (TMDs) are a subgroup of craniofacial problems and etiology is believed to be multi-faceted. Tooth grinding, facial clenching and genetic factors may initiate TMD and bio-behavioral studies suggest an association between TMD pain and depression, anxiety and post-traumatic stress disorder.

In this study, the research team sought to estimate the relative risk of depressive symptoms and anxiety on TMD pain over five years. More than 4,000 subjects participated and underwent medical examinations, oral health assessments, health-check interviews, and completed a psychiatric risk factor questionnaire. TMD pain was assessed from the oral health exams according to guidelines from the Academy of Orofacial Pain.

The investigators found that depressive symptoms were more strongly related to joint pain than muscle pain, and that anxiety symptoms were linked with muscle pain. The authors explained that depressive and anxiety symptoms may initiate muscular hyperactivity followed by muscle abnormality and altered muscle mechanics, which can cause inflammation and muscle pain. They also suggested TMD might be related to abnormal pain stimuli processing caused by imbalances in the neurotransmitters serotonin and catecholamines. So, TMD pain might reflect physical manifestation of anxiety or depression.

In support of previous published research, the authors concluded there is a strong to moderate relationship between symptoms of depression or anxiety and signs of TMD.