The strongest finding was that participants perceived themselves to be less distracted by aggressive and ruminative thoughts. Studies have shown that the tendency to engage in ruminative thoughts can turn a mood into depressive episodes.

People were given 2 grams per day of the Ecologic®Barrier probiotic containing 2.5 billion bacteria per gram of the following bacterial stains: Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, L. casei W56, Lactobacillus salivarius W24, and Lactococcus lactis (W19 and W58).