Association between periodontal diseases and bipolar disorder: implications for therapeutic interventions

Abstract

Chronic low-grade inflammation plays a role in the pathophysiology of bipolar disorder. Recent studies have shown that periodontitis can affect the central nervous system by activating inflammatory mediators in the brain. However, only a few studies have ex-amined the association between periodontitis and bipolar disorder. Here, we aimed to review the current evidence on the association between periodontal diseases and bipo-lar disorder, its potential mechanisms, and future research directions. Studies so far suggested that periodontal diseases were more common in patients with bipolar disor-der than in the general population. Patients with bipolar disorder generally have poor oral hygiene owing to poor self-care, smoking, alcohol abuse, and the effects of psycho -tropic medications. Proposed mechanisms underlying this association include the ef-fects of inflammatory mediators, direct invasion of oral microbiota, modulation of the neurotransmitter system, and impact on the vagus nerve and hypothalamus -pitu-itary-adrenal axis. Additional clinical studies examining the prevalence of periodontal diseases and their association with the clinical features of bipolar disorder are neces-sary. Clinical studies targeting the treatment of periodontal diseases for primary or sec-ondary prevention of bipolar disorder are warranted.