Correlation of the Gastrointestinal Tract and Depression

With more than 25% of psychological patients experiencing depression, a need for treatment is in high demand as current medications such as selective serotonin reuptake inhibitors (SSRI’s) are either ineffective or cause unwanted side effects. SSRI’s work by blocking the transport protein in the presynaptic neurons of the brain and allow for the collection of serotonin in the synapse to be utilized. Though the brain emphasized when discussing depression, the microbes residing in the gastrointestinal tract plays a significant role in serotonin availability.  With the GI tract producing more than 95% of serotonin, it is possible the microbial abundance is an underlying factor in the production of “natural” serotonin levels and depression. Much research has been pursued in efforts to identify the importance of GI microbes and the influence of diet and antibiotics on the microbial function. Fecal transplantation is a recent clinical resolution that could potentially replenish the GI tract of necessary microbes required for serotonin synthesis. With the success of fecal transplantation in clinical studies, the correlation between the GI tract, associated microbes, serotonin, and depression, one could utilize fecal transplantation to replenish the microorganisms needed to synthesize serotonin and decrease the prevalence of depression.