Introduction

Currently, it is estimated that 350 million people worldwide live with depression (up to 5% of the global population).¹ Further, US depression rates have risen significantly in recent years, with data from 2024-2025 demonstrating that approximately 18% of adults are undergoing treatment for or have signs of depression.² Despite these staggering figures, mental health, anxiety, and substance use disorders are still significantly under-reported and treatment is often delayed or avoided due to stigma or embarrassment. Anxiety, depression, and stress have also been linked to poorer oral health status and treatment outcomes.^3-8 This relationship has been linked to the alterations that stress may induce on the immune system. Additionally, adequate treatment and antidepressant agents have anti-inflammatory functions that may serve to improve outcomes during periodontal therapy,⁹ but their adverse effects on salivary flow may impact caries rates.¹⁰ Because of the high prevalence of anxiety and depression in the population and the importance of adequate treatment for oral and overall health outcomes, identification, screening, and referral of at-risk patients seen in the dental office is a critical part of ensuring overall patient wellness. This course seeks to identify risk screening tools to assess anxiety and depression in the patient population seeking dental care and to evaluate the link between these common mental health disorders and oral health.

Anxiety and depression are common in the United States. In general, nearly 1 out of every 3 adults will be diagnosed with depression in their lifetime.² Such depressive episodes may be situational and/or clinical and depression prevalence is significantly higher in women (24%) versus men (13%).² Educational level, household income, and regional locality are also associated with report of depression diagnosis.¹¹ Many people who experience depression also have other mental health conditions, particularly anxiety disorders, with up to 85% of individuals diagnosed with depression also meeting the criteria for an anxiety disorder.^12,1313Anxiety and depressive disorders are moderately heritable (approximately 40%), and evidence suggests shared genetic risk across the internalizing disorders and comorbidity of both conditions can make treatment more challenging.^12,14

Individuals with psychiatric disorders experience increased risk of systemic diseases, including diabetes mellitus, cardiovascular disease, autoimmune diseases, cancer, and chronic obstructive pulmonary disorder.^5,14-18 Chronic psychosocial stress and depression have also been shown to adversely effect therapy and outcomes of these conditions.¹⁸ Stress and depression have also been linked to higher overall rates of morbidity and mortality within the population across a range of systemic conditions. The mechanisms for these links may be manifold.^16-18 Chronic stress, which has been associated with anxiety disorders and depression, increases systemic inflammatory burden and is associated with damage to the brain region that controls mood, including the hippocampus and prefrontal cortex, making these conditions difficult to treat.^19-24

The interrelationship of anxiety and depression and periodontal disease is generally explained through the effects of these psychosocial conditions on the host immune response through a chronic stress mechanism.²⁵ A meta-analysis identified a significant association between anxiety disorders and/or depression and periodontitis.²⁶ The underlying reasons for this may be multifactorial, including increased xerostomia due to medications and/or an upregulation of sympathetic nervous system stimulation, a reduction in motivation for self-care behaviors, such as oral hygiene, in individuals with anxiety and depressive disorders, and/or a common inflammatory burden that may affect the host immune response.^5,26 Assessment of patients’ psychological well-being is critical to understanding their current disease state and their potential response to therapy.