Mouth bacteria partially spread depression and anxiety in newlywed couples

Summary

IntroductionOral microbiota dysbiosis is significantly correlated with various neuropsychiatric disorders, including autism spectrum disorder, dementia, Parkinson’s disease, schizophrenia, anxiety, epilepsy, and depression.1 Wingfield et al.2 demonstrated that the composition of the oral microbiota is significantly associated with depression in young adults who met the criteria for depression outlined in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (hereinafter referred to as DSM). They found that 21 bacterial taxa exhibited significantly different levels of abundance in depressed young adults. Specifically, there was an increase in Prevotella nigrescens and Neisseria spp., while 19 taxa showed a decrease in abundance. Oral microbiota exhibits variability influenced by individual factors, including oral hygiene practices, substance use, and tobacco consumption.1Recently, Simpson et al.3 demonstrated that the composition of the oral microbiota significantly correlates with symptoms of anxiety and depression in adolescents. Similar patterns have been observed in other populations, including pregnant women,4 patients experiencing burning mouth syndrome with psychiatric symptoms,5 individuals with anxiety, mood disorders, trauma- and stress-related disorders,6 and those with irritable bowel syndrome,7 among others.Salivary cortisol does not directly cause depression or anxiety but serves as an indicator of these disorders. The suggested mechanism of action is that the oral microbiota may directly compromise the blood-brain barrier or exert indirect effects through the oral microbiota-brain axis.1On the other hand, a diminished cortisol awakening response is linked to an increased likelihood of experiencing a negative and persistent progression of depression and/or anxiety disorders.8,9The first author has previously discussed how closeness may facilitate bacterial transmission and, consequently, impact microbiota-related research.10 In various ...