Probiotics and major depressive disorder

The gut microbiome is increasingly being recognised as an important player in the regulation of social behaviour, mood, and pain sensitivity. Through their relationship with nervous system signalling, their ability to regulate the immune system and their interaction with the gut-brain axis, the healthy gut microbiota appear to be essential for modulating hormones and neurotransmitters involved in stress and mood regulation.

In this pilot randomised clinical trial to assess the acceptability and tolerability of probiotics as adjunct therapy for individuals with major depressive disorder (MDD), 49 adults with MDD who did not respond to prescription antidepressants, were given a 14-strain probiotic supplement (providing 8 billion CFUs) or placebo daily for 8 weeks alongside their prescription antidepressant medication. Besides assessing the retention, acceptability and tolerability of the interventions, other outcomes included the effect on clinical symptoms of depression and anxiety.

Results showed that both groups demonstrated improvements in their symptoms during the study, but greater improvements were observed in the probiotic group from the fourth week onward.

Researchers concluded that probiotic supplementation is a promising adjunctive therapy for individuals with MDD, and that further larger studies are needed to confirm the efficacy of probiotic supplementation on clinical outcomes in patients with MDD.

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