Effect of Probiotics on Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

It has been reported that gut probiotics play a major role in the bidirectional communication between the gut and the brain. Probiotics may be essential to people with depression, which remains a global health challenge, as depression is a metabolic brain disorder. However, the efficacy of probiotics for depression is controversial. This study aimed to systematically review the existing evidence on the effect of probiotics-based interventions on depression. Randomized, controlled trials, identified through screening multiple databases and grey literature, were included in the meta-analysis. The meta-analysis was performed using Review Manager 5.3 software using a fixed-effects model. The meta-analysis showed that probiotics significantly decreased the depression scale score (MD (depressive disorder) = −0.30, 95% CI (−0.51–−0.09), p = 0.005) in the subjects. Probiotics had an effect on both the healthy population (MD = −0.25, 95% CI (−0.47–−0.03), p = 0.03) and patients with major depressive disorder (MDD) (MD = −0.73, 95% CI (−1.37–−0.09), p = 0.03). Probiotics had an effect on the population aged under 60 (MD = −0.43, 95% CI (−0.72–−0.13), p = 0.005), while it had no effect on people aged over 65 (MD = −0.18, 95% CI (−0.47–0.11), p = 0.22). This is the first systematic review and meta-analysis with the goal of determining the effect of probiotics on depression. We found that probiotics were associated with a significant reduction in depression, underscoring the need for additional research on this potential preventive strategy for depression.

Efficacy of probiotics on anxiety-A meta-analysis of randomized controlled trials

“…Our findings are also different from that of three previously published meta-analyses (Huang et al, 2017;Huang, Wang, & Hu, 2016;McKean, Naug, Nikbakht, Amiet, & Colson, 2017) assessing the effect of probiotics on depression, anxiety, or psychological symptoms. The inconsistency in findings between our study and the meta-analysis of Huang et al (2017) is particularly interesting because we addressed the same topic but found very different results.…”

Gut microbiota‐immune‐brain interactions in chemotherapy‐associated behavioral comorbidities

“…49 In parallel, the use of probiotics (defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host) is associated with decreased depressive symptoms in healthy adults as well as patients diagnosed with MDD. 50, 51 …”

“…While implementing probiotic interventions to ameliorate psychiatric disorders is a relatively novel approach, most available clinical trials report reduced symptoms of depression and anxiety. 50, 103 For example, consumption of a mixture of Lactobacillus casei, Lactobacillus acidophilus, and Bifidobacterium bifidum by patients with MDD reduces symptoms of depression. 51 This same mixture of probiotics also increases cognitive function in patients diagnosed with Alzheimer's disease.…”

Efficacy of Probiotics on Anxiety: A Meta-analysis of Randomized Controlled Trials

“…Based on this finding, some studies have used active probiotics to treat anxiety disorders. Probiotics, defined as living microorganisms, are believed to provide health benefits [14,15]. Probiotics refer to ingested microorganisms with benefits for both humans and animals.…”