Repeated episodes that limit oral function intensify anxiety, depressive symptoms, and declines in oral health–related quality of life (OHRQoL) among individuals with Recurrent Aphthous Stomatitis (RAS). Yet, the precise contributors to these psychological burdens and OHRQoL reductions are still not fully clarified.This study sought to measure psychological distress and OHRQoL impairment in people with RAS and to determine adjustable risk factors underlying these declines to guide focused intervention strategies. A cross-sectional survey was administered to RAS participants using both online and paper formats. Data on demographic and clinical variables, along with anxiety, depression, and OHRQoL scores, were obtained and evaluated. Extended ulcer duration and choosing Traditional Chinese Medicine (TCM) treatments emerged as notable predictors for increased anxiety and depression in RAS patients. Frequent intake of fried foods (OR: 3.88, p = 0.006) heightened anxiety risk. Individuals reporting higher fruit consumption (B: 3.42, p < 0.001) showed more pronounced anxiety symptoms. Spicy food intake (B: −1.18, p < 0.001) was associated with reduced anxiety. Among anxious patients, regular vegetable consumption (B: −4.820, p < 0.001) was linked with lower anxiety levels. Larger ulcer size (B = 2.09, p = 0.017), more frequent recurrences (B = 4.74, p < 0.001), and greater fried food intake (B = 2.19, p = 0.002) intensified depressive symptoms. Increased pain severity, frequent fried food intake (B = 2.68, p = 0.004), moderate fruit consumption (B = 1.39, p = 0.019), and preference for TCM (B = 2.08, p = 0.022) were related to poorer OHRQoL. Ulcer-related features, dietary patterns, and TCM preference contributed to elevated psychological distress and diminished OHRQoL in RAS populations. Tailored psychological support may help stabilize mental well-being and OHRQoL, lessen ulcer recurrence, and improve patient outcomes.
