Anxiety, depression, and pain in burning mouth syndrome: first chicken or egg?

Background: Burning mouth syndrome (BMS) is an idiopathic and chronic pain condition for which patients may experience high levels of pain, anxiety, and depression. So far, it has not yet been well investigated whether specific psychiatric features (anxious traits, personality disorder, or somatization) may play a role in the BMS pathogenesis or whether some BMS symptoms, or BMS itself, may cause secondary psychiatric symptoms.

Objective: The aim of this study was to evaluate the relationship between pain, depression, and anxiety in BMS and healthy patients in order to hypothesize a possible underlying pathogenetic model.

Methods: Fifty-three patients with BMS and 51 healthy volunteers matched for sex and age were enrolled. All patients underwent a physical examination, laboratory screening tests, and psychiatric assessment with the following instruments: Visual Analog Scale, the Hamilton Rating Scale for Depression, the State-Trait Anxiety Inventory Form Y 1-2 (STAI Y1-Y2), and the Symptom Checklist-90-Revised (SCL-90-R).

Results: BMS patients and healthy volunteers showed a statistically significant difference in psychiatric features: Regression analysis showed that pain is affected by depression (R = 0.373; R(2) corrected = 0.123; F = 8.563; P < .005), and depression is affected by anxiety (R = 0.512; R(2) corrected = 0.248; F = 18.519; P < .001). BMS patients have statistically significant higher scores of anxiety (STAI Y1, P = .026 and STAI Y2, P = .046) and depression (P < .001), and higher SCL-90-R scores on somatization (P = .036) and hostility dimensions (P = .028) than the control group.

Conclusions: We may hypothesize that anxiety could determine a secondary demoralization in BMS patients (depression) and depressive symptoms could contribute to pain, accordingly. Therefore, pain could be a somatic feature of depression. Our findings provide an example of a possible pathogenetic model for BMS.