Anxiety, depression may be triggered by stress-induced changes to gut bacteria

By Honor Whiteman, Medical News Today

Increasingly, researchers are investigating how gut bacteria impact health. In November 2014, for example, Medical News Today reported on a study revealing how gut bacteria influence weight, while another study associated gut bacteria with Parkinson’s disease.

According to senior study author Premysl Bercik, associate professor of medicine at the Michael G. DeGrotte School of Medicine at McMaster University in Canada, and colleagues, it has long been known that gut bacteria can also influence behavior.

However, the majority of studies investigating this association have used healthy, normal mice, says Bercik. For their study, the team used two groups of mice; one group had normal gut bacteria while the other group had no gut bacteria.

Some of the mice in each group were subjected to early-lifestress, triggered by separation from their mothers for 3 hours daily from the age of 3-21 days.

Neonatal stress changed gut bacteria in mice, inducing anxiety and depression

In mice with normal gut bacteria, the team found stressed mice developed abnormal levels of the stress hormone corticosterone, alongside anxiety and depression-like behavior. What is more, these mice showed impaired gut function.

However, while stressed mice with no gut bacteria still experienced a rise in corticosterone and impaired gut function, they did not develop anxiety and depression-like behavior. Read More