Jenni Hetletved



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Document Type



Major Depressive Disorder (MDD) is a crippling condition that affects millions of people worldwide. Serotonin reuptake inhibitors (SSRIs) are the staple treatment adjunct to psychotherapy. Recently, the connection between gut health, specifically the gut brain axis, has been researched to look at the connection between gut microbiota and its effect on depressive symptoms. This meta-analysis evaluates the connection between gut microbiota and depression as well as the effectiveness of SSRI therapy on depression. Results show a significant change in gut microbiota with short term change to a Mediterranean diet (MD) compared to a Western diet (WD). This change in gut microbiota has also shown improvement in depressive symptoms. This analysis also found a link to degradation of serotonin receptors in the hippocampus from certain gut bacteria found in a WD. SSRI therapy showed improvement of symptoms within 4 weeks according to some studies while other studies disagreed showing minimal improvement in depressive symptoms short term, with little increase in effectiveness long term.


Physician Assistant Studies

Degree Name

Master of Physician Assistant Studies (MPAS)

First Advisor

Staveteig, Mindy

Publication Date

Spring 2023


Depression, Major Depressive Disorder, Gut-Brain-Axis, Gut Microbiota, Probiotics

The Effectiveness of the Gut-Brain-Axis versus SSRI for Treatment and Management of Depression