Researchers Say Kissing Can Transmit Depression and Anxiety

The study observed 268 newlywed couples in Iran over a period of six months. Participants were asked to complete psychological assessments, provide saliva samples for cortisol measurement (a key stress hormone), and undergo DNA analysis of their oral bacteria. The results were striking: in couples where one partner had symptoms of depression or anxiety, the other partner—originally healthy—began to develop similar symptoms over time. This transmission of mental health symptoms seemed to coincide with changes in the oral microbiome, suggesting a potential microbial link.