Scientists: depression and anxiety can be transmitted through kisses

Scientists discover: depression and anxiety can "kiss" - oral bacteria can transmit mental disorders

An international group of researchers has identified a surprising fact: in just six months of living together with a person suffering from depression or anxiety, a healthy partner can become "infected" with these conditions through the oral microflora.

As reported by TUT.AZ, the results of a large-scale study were published in the journal Exploratory Research and Hypothesis in Medicine. Scientists analyzed data from 1,740 married couples who had been married for about six months. Among the participants, 268 people were mentally healthy, while their partners suffered from depression, anxiety, and sleep disorders. All volunteers underwent standardized psychological tests and provided saliva samples to determine stress hormone levels and analyze the microbiome using DNA sequencing.

The results were astonishing: over time, the mental health indicators of initially healthy spouses noticeably deteriorated. In parallel, the composition of their oral microflora increasingly resembled the microbiome of partners with mental disorders. Bacteria from the families Clostridia, Veillonella, Bacillus, and Lachnospiraceae reproduced particularly actively, which, according to scientists, can weaken the protective blood-brain barrier and affect brain functioning.

Ordinary household contacts – kisses, shared meals, or even simply breathing near each other – proved to be effective pathways for exchanging millions of bacteria. Researchers believe that this transmission of microflora may partially explain why one partner in a couple develops symptoms of depression and anxiety.

Notably, women demonstrated greater susceptibility to this process: changes in their microbiome and deterioration of mental state were significantly more pronounced. Additionally, healthy spouses showed increased levels of cortisol – the stress hormone, which further indicates the activation of stress reactions in the body.

Scientists are confident that their discovery will help to better understand the biological mechanisms of the spread of mental disorders in close relationships and will be a valuable contribution to developing recommendations for psychologists and therapists.