Bidirectional Associations of Temporomandibular Joint Disorders with Major Depressive and Anxiety Disorders

Objectives: Mounting evidence indicates the associations of temporomandibular disorders (TMD) with depression and anxiety symptoms. However, the temporal and casual relationships between TMD and depression and between TMD and anxiety must be further clarified. Methods: This study is a retrospective cohort analysis that employed data from the Taiwan National Health Insurance Database and comprised the following sub analyses: temporomandibular joint disorders (TMJD) as the cause of subsequent major depressive disorder (MDD) or anxiety disorders (AnxDs) and TMJD as the consequence of MDD or AnxDs. Patients with antecedent TMJD (N = 12,152 for the MDD study and 11,023 for the AnxD study), MDD (N = 28,743), or AnxDs (N = 21,071) and their respective control cohorts were identified between January 1, 1998 and December 31, 2011. The control cohorts (1:10) were matched by age, sex, income, residential location, and comorbidities. Individuals with subsequent new-onset TMJD, MDD, or AnxDs were identified from January 1, 1998 to December 31, 2013. The risk of the outcome disorders of the individuals with antecedent TMJD, MDD, or AnxD were estimated using Cox regression models. Results: Patients with TMJD had an approximately 3-fold higher risk (hazard ratio [HR]: 3.98, 95% confidence interval [CI]: 3.28-4.84) of subsequent MDD development and a 7-fold higher risk (HR: 7.26, 95% CI: 5.90-8.94) of AnxD development than those without TMJD. Antecedent MDD and AnxDs were predictive of 5.80-fold (95% CI: 4.81-6.98) and 8.29-fold (95% CI: 6.67-10.30), respectively, increases in the risk of subsequent TMJD development. Conclusions: Our results demonstrate that precedent TMJD and MDD/AnxDs are associated with elevated risks of subsequent MDD/AnxDs and TMJD developments and indicate temporal associations of TMJD with MDD and AnxDs are bidirectional.