Study Links Dog Ownership to Better Teen Mental Health via Microbes

A new study from researchers in Japan suggests that owning a dog during adolescence may enhance teenagers' mental health by reshaping the microbes in their mouths, fostering more empathetic and social behaviors.

The research, led by Takefumi Kikusui at Azabu University, examined survey data from 343 healthy adolescents aged 12 to 14 in Tokyo as part of the Tokyo Teenager Cohort Study. About one-third of the participants lived with a family dog. At age 13, dog ownership predicted better mental health outcomes by age 14, including lower rates of social withdrawal, aggression, delinquent behavior, thought problems and overall social difficulties. The team controlled for factors such as sex and household income to isolate these effects.

To explore a potential biological mechanism, the researchers analyzed saliva samples from 247 non-dog owners and 96 dog owners. While the overall diversity of microbes was similar between the groups, the composition differed notably. Dog owners had higher levels of certain bacteria, including several Streptococcus species and Prevotella, which prior studies have linked to reduced depressive symptoms and anti-inflammatory effects in the gut.