The effectiveness of L. reuteri NK33 and B. adolescentis NK98 in decreasing stress, anxiety, and sleep disturbances, as well as measuring some blood biomarkers, particularly pro-inflammatory cytokines like IL-6, was demonstrated in a double-blind, randomized, placebo-controlled clinical trial that included 156 healthy individuals between the ages of 19 and 65 who had undergone psychological stress and had subclinical symptoms of depression or anxiety. This evidence concerns the gene IL6 and depressive disorder.