Effect of psychobiotics on psychometric tests and inflammatory markers in Major Depressive Disorder: Meta-analysis of randomized controlled trials with meta-regression

This 2021 review evaluated randomized clinical trials that used probiotics or placebos in patients with major depressive disorder (MDD) and reported any psychometric score. The overall aim was to assess the effect of taking a new class of probiotics-psychobiotics on psychometric scales and the immune system. Medical databases were searched for relevant research articles from database inception until 22 April 2021, yielding ten eligible studies. The mean duration of the studies was around 49 days. The participants were mostly women and averaged 38 years of age. The results showed that probiotics may alleviate symptoms of major depressive disorder. The effectiveness of the probiotic treatment appeared to be related to time of administration. Psychobiotic therapy also tended to be more effective in men. To conclude, psychobiotics hold great potential in the treatment of major depressive disorder, although it is difficult to recommend a particular strain, dosage, or treatment duration. [NPID: probiotics, psychobiotics, gut microbiota, gut health, major depressive disorder, depression, review]

Year: 2021

Reference: Misera, A., Liśkiewicz, P., Łoniewski, I., Skonieczna-Żydecka, K., & Samochowiec, J. (2021). Effect of Psychobiotics on Psychometric Tests and Inflammatory Markers in Major Depressive Disorder: Meta-Analysis of Randomized Controlled Trials with Meta-Regression. Pharmaceuticals (Basel, Switzerland), 14(10), 952. https://doi.org/10.3390/ph14100952

Related Studies

Probiotics reduce negative mood over time: the value of daily self-reports in detecting effects

Growing interest in the microbiome–gut–brain axis has led researchers to explore how gut bacteria influence emotional well-being. Probiotics have emerged as a promising area for microbiome-based interventions in mental health; however, previous studies have yielded inconsistent results, particularly in healthy individuals. In a randomized, double-blind, placebo-controlled study by Johnson & Steenbergen (2025) involving 88 healthy […]

Anxiolytic effects of a galacto-oligosaccharides prebiotic in healthy females (18–25 years) with corresponding changes in gut bacterial composition

In this 2021 study, healthy female adults were assessed on mood and well-being after taking galacto-oligosaccharides (GOS) prebiotic supplements every day for 4 weeks. Stool samples were collected before and after the intervention to analyze their gut microbiota. This study focused on nutritional supplementation in participants transitioning between late adolescence and early adulthood since these […]