Family Dog May Boost Mental Health in Teens Via the Microbiome

Dogs are famously man’s best friend, armed with unlimited tail wags and slobbery kisses that can make any gloomy mood disappear in an instant. It’s no surprise that dogs greatly benefit people’s mental health.

For instance, researchers like Takefumi Kikusui, an animal behaviorist at Azabu University, found that people who lived with dogs both early and later in life had higher measures of companionship and social support.¹ Other studies found that living with a dog can influence the owner’s gut microbiota.² This motivated Kikusui to further investigate this relationship.

“Raising dogs has beneficial effects, especially for adolescents, and these effects may be mediated through symbiosis with microorganisms,” he explained in a press release. In a recent study, published in iScience, Kikusui’s team found that young people who own dogs have higher well-being scores and distinct microbiomes than their dogless peers.³ These findings suggest that family dogs can boost mental health through microbiota-driven changes.

First, the researchers analyzed mental health and behavioral problems among 13-year-old adolescents who owned dogs and those who did not. Using a child behavior checklist, the team found that the psychological scores, which included delinquent behavior and aggression, were significantly lower in adolescents with a dog at home compared to those without a dog.

To further investigate whether the microbiome correlated with this behavior, the researchers took salivary microbiota samples from the two groups. Although the oral microbiome diversity was similar between the teen groups, the dog-owner samples had more Streptococcus and Prevotella species. Notably, a higher abundance of Streptococcus was negatively associated with delinquent behavior, suggesting that dogs may influence their teen owner’s psychological scores, in part, through changes in the microbiota.

To have a better idea of whether these microbes could influence social behavior, the researchers took the teens’ oral microbiota and transplanted them into germ-free mice. Mice with the dog-owning microbiome exhibited more social behaviors, such as sniffing other mice, compared to mice with non-dog-owning microbiomes. They also showed a stronger tendency to approach and interact with trapped cage-mates, suggesting that these bacteria may encourage greater social engagement.

While the researchers acknowledge that it is difficult to draw direct comparisons between human and mouse behavior, the findings hint at yet another benefit of welcoming a furry companion into the family.