A recent randomized controlled trial (RCT) has discovered that after an 8-week supplementation period with probiotics in individuals with major depressive disorder (MDD) who were also taking antidepressants, there was a significant improvement in depressive symptom scores. Furthermore, the probiotic supplement, consisting of 14 different strains, significantly improved scores related to anxiety symptoms in one of the two assessments conducted when compared to the placebo group.
“To the best of our knowledge, this is the first trial in a Western population to demonstrate the safety, acceptability, and therapeutic potential of a readily available and scalable probiotic intervention in patients with MDD,” emphasizes the study funded by ADM Protexin.
Professor James Stone, the senior investigator of the study from Brighton and Sussex Medical School, underlines, “Non-response or partial response to antidepressants is a major problem, and this study represents an important initial step in exploring the therapeutic potential of probiotics as a treatment for depression. We found that probiotics were a well-received and tolerable supplement for individuals already taking antidepressant medications. This now paves the way for studies to examine whether we observe these beneficial effects of probiotics on depression and anxiety in larger populations of patients.”
Depression Treatment:
The prevalence of mental health conditions has been on the rise. However, it has been noted that 60% of individuals with MDD do not respond adequately to first-line treatments to some extent. Consequently, there has been significant interest in exploring natural alternatives for such conditions. A wealth of evidence points to the involvement of the gut-brain axis in the pathophysiology of MDD, suggesting the potential for microbiome-targeted treatments.
Recent studies have emphasized the effectiveness of probiotic intervention in reducing depressive symptoms when used in conjunction with antidepressants. Nevertheless, the evidence in this field remains limited, making it difficult to draw conclusions regarding the safety and efficacy of probiotics.
Hence, the current RCT aimed to advance this research by investigating the efficacy of probiotic intervention in individuals with MDD who were currently taking antidepressant medication without experiencing a complete response.
Study:
The researchers recruited 49 adults aged 18-55 from primary and secondary care services in London. Subjects were administered either a daily dose of four capsules containing a multi-strain probiotic (8 billion CFUs/day) or a placebo over an 8-week period. The Bio-Kult Advanced probiotic, developed by ADM Protexin, included 14 bacterial strains, including Bacillus, Bifidobacterium, Lactobacillus, Lactococcus, and Streptococcus species.
Measures for clinical symptoms of depression were obtained using the Hamilton Depression Rating Scale (HAMD-17) and the inventory of Depressive Symptomatology (IDS) scores. Anxiety scores were measured using the Hamilton Anxiety Rating Scale (HAMA) and General Anxiety Disorder GAD-7 scores.
Key Findings:
Analysis using mixed linear models revealed that those treated with the probiotic showed greater improvement in depressive symptoms in both related tests compared to the placebo group. Additionally, there was a significant reduction in anxiety symptoms according to the HAMA scores, although no significant changes were observed in the GAD-7 scores among those who received the probiotic.
Significance:
“Compared with the placebo group, the probiotic group exhibited greater improvement in depressive symptoms with moderate effect sizes, which are comparable to those reported in earlier meta-analyses. Participants in the probiotic group experienced, on average, a reduction of 1 severity grade on both depression rating scales,” summarizes the report.
The significance of these findings in terms of acceptability, tolerability, and the effect size of probiotic treatment will contribute to the advancement of research in this area and encourage further studies involving larger sample sizes.
Dr. Richard Day, VP of Medical Affairs at ADM, underscores, “This trial is one of the few clinical studies to assess the benefits of supplementing the diet with probiotics alongside standard care antidepressant medication. These exciting results add to our understanding of the link between the gut microbiome and mental health.”
