Date of Award


Document Type

Open Access Thesis

Degree Name

MS in Physician Assistant Studies (PA)


Physician Assistant Studies

First Advisor

Vanessa S. Bester, EdD, PA-C, DFAAPA


Background: Depression and anxiety continue to be a healthcare burden worldwide. Current depression and anxiety treatments include medications and psychotherapy; however, for many patients this is not enough. Literature has recently come out detailing the gut-brain axis and its potential impact on mental health.

Purpose: This literature review sought to answer the question if probiotics could play a role in the treatment of depression and anxiety. Specifically, does supplementation with a probiotic improve clinical outcome measures of depression, anxiety, or both? Methods: A comprehensive literature review was conducted using PubMed and Google Scholar using the search terms probiotics, depression, and anxiety. Studies were selected based upon meeting certain inclusion and exclusion criteria. In total eighteen studies met the inclusion criteria and are reviewed in detail.

Conclusions: Among 24 research studies analyzed based on outcomes, 16 of them found significant improvements in depression outcomes. In nine of fifteen studies, anxiety outcome measures showed a significant improvement. It is important to note there a several limitations to these studies such as a small sample size and rigorous inclusion and exclusion criteria which make the results less generalizable to the public. Ultimately, more high-powered studies measuring similar outcome measures are needed to sufficiently answer the question above.


SC 11.PAS.2022.DeCleene.K

Included in

Psychiatry Commons