Depression and Anxiety as Predictors of Pain and Sensory Thresholds in Adults with and Without Temporomandibular Disorder: A Case–Control Study

Aim: Temporomandibular disorders (TMDs) are often associated with psychological distress and altered pain perception. However, the relationship between depression, anxiety, and sensory/pain thresholds in TMD remains underexplored. The present study aimed to assess the association of depression and anxiety with sensory and pain thresholds in adults with and without TMD using standardized electrical stimulation. Materials and Methods: This observational case-control study included 56 adults with TMD and 56 matched healthy controls. Psychological distress was evaluated using the SCL-90-R questionnaire. Sensory and pain thresholds were assessed via electrical stimulation of the dental pulp. The sensory threshold was the minimum intensity of a stimulus, and pain threshold is the minimum intensity of a stimulus that triggers the perception of pain. Statistical analyses included Mann-Whitney U, Kruskal-Wallis, Spearman correlation, and multivariate logistic regression, adjusted for age and gender. Results: TMD subjects demonstrated significantly higher depression and anxiety scores than controls (P < 0.01). Pain thresholds were negatively correlated with depression and anxiety in both groups (r ≈ -0.63 to -0.66, P < 0.001), while anxiety correlated with lower sensory thresholds in TMD subjects only (r = -0.37, P < 0.01). Multivariate analysis revealed that a low pain threshold was independently associated with moderate/severe depression (OR = 4.38; 95% CI: 1.13-17.04), while a low sensory threshold was linked with moderate/severe anxiety, TMD status, female gender, and older age. Conclusion: Depression is independently associated with reduced pain thresholds in both TMD and healthy subjects. Anxiety is specifically linked to sensory threshold reduction in TMD patients. These findings underscore the need to integrate psychological assessment in chronic orofacial pain management.