Assessment of optimal combinations of therapeutic probiotics for depression, anxiety, and stress

Abstract Background Accumulating data show that probiotics may be beneficial for reducing depressive, anxiety, and stress symptoms. However, the best combinations and species of probiotics have not been identified. The objective of our study was to assess the most effective combinations and components of different probiotics through network meta-analysis. Method A systematic search of four databases, PubMed, Web of Science, Cochrane, and Embase, was conducted from inception to 11 January 2024. The GRADE framework was used to assess the quality of evidence contributing to each network estimate. Results We deemed 45 trials eligible, these included 4053 participants and 10 types of interventions. The quality of evidence was rated as high or moderate. The NMA revealed that Bifidobacterium exhibited a greater probability of being the optimal probiotic species for improving anxiety symptoms (SMD = −0.80; 95% CI −1.49 to −0.11), followed by Lactobacillus (SMD = −0.49; 95% CI −0.85 to −0.12). In addition, for multiple strains, compared with the other interventions, Lactobacillus + Bifidobacterium (SMD = −0.41; 95% CI −0.73 to −0.10) had a positive effect on depression. Conclusion The NMA revealed that Lactobacillus and Bifidobacterium had prominent efficacy in the treatment of individuals with anxiety, depression, and combination of Lactobacillus + Bifidobacterium had a similar effect. With few direct comparisons available between probiotic species, this NMA may be instrumental in shaping the guidelines for probiotic treatment of psychological disorders.