A new study reveals how a child’s early gut microbiome may influence their risk of developing depression, anxiety, or other internalizing symptoms during childhood. According to researchers at the University of California, Los Angeles (UCLA) Health, US, the effect relates to the way bacteria affect communication across emotion-related brain networks. The observational study found that young children with a higher amount of gut bacteria in the Clostridiales order and Lachnospiraceae family were more at risk of experiencing internalizing symptoms — an umbrella term that covers symptoms of depression and anxiety — in middle childhood.