ABSTRACT
BACKGROUND: The gut microbiota impacts on central nervous system (CNS) function via the microbiota-gut-brain axis. Thus, therapeutics targeting the gut microbiota such as probiotics have the potential for improving mental health. This meta-analysis synthesizes the evidence regarding the impacts of probiotics on psychological well-being, psychiatric symptoms and CNS functioning. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied for executing this review using the databases PubMed, Web of Science and Cochrane Library. The data were summarized at qualitative and quantitative level. RESULTS: Fifty-four randomized placebo-controlled studies were included, of which 30 were eligible for meta-analysis. If investigated, the probiotics mostly exerted effects on CNS function. Most probiotics did not affect mood, stress, anxiety, depression and psychiatric distress when compared to placebo at the qualitative level. At quantitative level, depression and psychiatric distress improved slightly in the probiotic condition (depression: mean difference -0.37 (95% CI: -0.55, -0.20); p ≤ 0.0001; psychiatric distress: mean difference -0.33 (95% CI: -0.53, -0.13); p = 0.001). CONCLUSIONS: To date it is unclear to which extent and in which specific areas next generation probiotics selected and developed for their ability to improve psychiatric condition and potentially other CNS functions are promising.
Subject(s)
Gastrointestinal Microbiome , Probiotics , Anxiety Disorders/therapy , Central Nervous System , Depression/drug therapy , Humans , Probiotics/therapeutic useABSTRACT
BACKGROUND: Functional gastrointestinal disorders such as irritable bowel syndrome (IBS) report clinical improvement following probiotic therapy, but whether psychiatric comorbidity and quality-of-life in IBS improves directly or in directly is unknown. This meta-analysis synthesized the evidence regarding the effects of probiotics on quality of life (QoL), anxiety and depression in IBS. METHODS: The review was executed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the databases PubMed, Web of Science and Cochrane Library. For QoL, the data were meta-analyzed, and for anxiety and depression a qualitative analysis was performed. RESULTS: Thirty-five placebo-controlled studies were included of which 11 were eligible for meta-analysis. QoL improved with probiotic and placebo similarly, with the probiotic interventions slightly superior (mean QoL difference-0.36 (95% CI: 0.07, 0.64); p = 0.01). Anxiety and depression were similar between placebo and probiotic groups following therapy. CONCLUSION: For IBS, probiotic therapy improved QoL, but had no effects on anxiety and depression. However, the applied probiotics were not developed for selective effects on psyche and the brain. Therefore, it remains to be shown whether or not patients with IBS would benefit from second generation probiotics developed for these central effects (psychobiotics).