Gut Microbiota in Depression: A Focus on Ketamine

Abstract

According to the WHO, major depressive disorder is the leading cause of disability worldwide, and it is a major contributor to the overall global burden of disease. The pathophysiology of this common and chronic disease is still not completely understood. The gut microbiome is an increasingly recognized environmental factor that can have a role in depression, acting through the gut–microbiota–brain axis. The available treatment for depression is still insufficient since 30% of patients are treatment-resistant. There is an unquestionable need for novel strategies. Ketamine is an effective antidepressant in treatment-resistant patients. It is suggested that the antidepressant effect of ketamine may be partially mediated by the modification of gut microbiota. In this study, we presented a review of data on gut microbiota in depression with special attention to the effect of ketamine on the microbiome in animal models of depression. Earlier reports are preliminary and are still insufficient to draw firm conclusion, but further studies in this field might help to understand the role of the gut–brain axis in the treatment of depression and might be the ground for developing new effective treatment strategies.

Are neuromodulation interventions associated with changes in the gut microbiota? A systematic review

“…For instance, the reported increase of the genus Lactobacillus after the final ECT session in Kanayama et al (2021) might (also) be ascribed to ketamine, which was used as an anesthetic during ECT sessions and has been shown to increase the abundance of Lactobacillus in rats in low doses (2.5 mg/kg). Thus, it is unclear whether this increase was due to induction of seizures and/or to ketamine's effects on the gut microbiota (Wilkowska et al, 2021). Similarly, Lubomski et al (2022) found initial alterations in several bacteria (i.e., Clostridium_XlVa, Bilophila, Pseudoflavonifractor, Dorea) that did not sustain after four weeks of DBS treatment.…”

Effects of dog ownership on the gut microbiota of elderly owners

“…In addition, gut microbiota can significantly affect intestinal mucin, especially Akkermansia muciniphila , which can significantly improve the thickness of mucin [ 7 ]. The gut microbiota can affect host health and is associated with multiple diseases, such as diabetes and depression [ 8 , 9 ]. The colonization or increase of probiotics is beneficial to the treatment of diseases [ 10 ].…”

The Role of Probiotics and Their Metabolites in the Treatment of Depression

“…Ketamine is a new and effective antidepressant in treatment-resistant individuals. It is recognized that the antidepressant impact of ketamine might be partially mediated by the modification of gut microbiota [ 24 ]. However, antidepressants are not the first-line treatment in cases of mild depression.…”