An unhealthy gut can affect a person's mental and physical health as it leads to loss of immunity, and chances of developing conditions such as gastrointestinal disorders, cardiovascular diseases, anxiety, stress and depression.

A new study suggests that patients on antidepressants may have reduced symptoms of mental disorders when their gut health is improved with probiotics.

Researchers analyzed 49 adults diagnosed with major depressive disorder, who did not have a complete response to prescription antidepressants. The participants were given antidepressants for eight weeks. Along with the treatment, 24 of them were given a probiotic supplement that contained 14 strains of bacteria, and the rest of them were given an identical placebo.

All the participants showed improvements in symptoms after eight weeks. However, those who were supplemented with probiotics showed marked improvements from week four onward.

Researchers observed that probiotics have a strong effect on reducing both depression and anxiety, with more effect on symptoms of anxiety.

"Non- or partial response to antidepressants is a huge problem and this study is an important first step in exploring the therapeutic potential of probiotics as a treatment for depression. We found that probiotics were an acceptable and tolerable supplement in people already taking antidepressant medications. This now paves the way for studies looking at whether we see these beneficial effects of probiotics on depression and anxiety in larger populations of patients," said James Stone, a senior investigator of the study.

It is estimated that 280 million people suffer from depression worldwide. Studies have shown that three in five people with depression do not fully respond to first-line treatments using antidepressants and continue to show symptoms.

The latest study suggests the use of probiotics as an adjunctive treatment along with antidepressants while paving the way to further investigate the benefits of probiotics on mood and mental health.

"The gut-brain axis is a truly fascinating and rapidly evolving area of microbiome research. The findings of this pilot study are an important step forward in our understanding of the role of probiotics in mood and mental health," explained Dr. Viktoriya Nikolova, the study's first author.