### Uncovering the Influence of Microbiome on Mental Health: An Emerging Area of Research in Neuropsychiatry
Our bodies are home to trillions of microorganisms collectively known as the microbiome. This massive ecosystem of bacteria, viruses, fungi, and other microorganisms reside largely in our gut, but also occupy other areas such as our skin or lungs. It plays a vital role in our body functionalities, from digestion to immunity to metabolism. Lately, however, research is digging deeper into a new facet – the significant connection between the gut microbiome and mental health. This emerging domain of research is generating fascinating insights, breaking new grounds in neuropsychiatry.
#### The Gut Between the Brain and Mental Health
The existence of a “gut-brain axis,” the bidirectional line of communication between the gut and the brain, has been variously acknowledged by scientific research. This bond is anchored on the vagus nerve – the tenth cranial nerve – that connects the brain to a fleet of organs including the gut. This axis is believed to communicate not only physical but also psychological information between the gut and the brain. The gut feelings we often experience might not be figments of the imagination, but actual signals emanating from this complex network.
#### The Microbiome: A New Actor on the Scene
In light of the gut-brain axis, researchers are beginning to understand that microbiome, as the prolific residents of the gut, might have a say in our mental health. Studies have revealed that individuals dealing with psychiatric conditions such as depression, anxiety, and even autism spectrum disorders often have a different gut microbiome composition compared to healthy individuals. But is this correlation actually causation? Could our gut microbes be contributing to our mental states?
#### The Microbiome-Mood Connection
Experimental studies performed on rodents have illuminated intriguing aspects of this connection. For instance, when microbiota from “depressed” mice were transplanted to “healthy” mice, the latter group began to exhibit behaviors suggestive of depression. Similarly, fecal microbiota transplants (FMT) from humans with depression to microbiome-free mice induced depressive-like behaviors in the mice.
What’s more, certain strains of bacteria such as *Lactobacillus* and *Bifidobacterium* have been shown to generate neuroactive substances like Gamma-aminobutyric acid (GABA) – a chief inhibitory neurotransmitter in mammalian central nervous system. Irregular GABA activity is often linked to mood disorders, anxiety, and depression.
#### Closing Thoughts and Future Prospects
Admittedly, we are only beginning to unravel the mysteries of our microbiota. This microscopic world that resides within us undeniably influences our health, for better or worse. However, applying this knowledge to develop targeted interventions or treatments in neuropsychiatry is a giant leap. While studies hint at potential for probiotics to aid some mental illnesses, the overly commercialized reality of these ‘live beneficial bacteria’ often oversimplifies their actual interaction within the labyrinthine world of our microbiome.
Future research needs to systemically map the microbial footprint in various mental health disorders, all the while acknowledging the interplay of various factors like genetics, diet, age, environment and more. Moreover, a push towards ethical regulations around potentially therapeutic microbial interventions such as FMT is also crucial.
The hidden influence our microbiome has on our mental health is an exciting area of research with massive promises for the field of neuropsychiatry. It truly attests to the belief that to understand the human condition, we must look not only around us, but also within.
**Sources:**
1. Foster JA, McVey Neufeld KA. Gut-brain axis: how the microbiome influences anxiety and depression. Trends Neurosci. 2013;36(5):305-312. doi:10.1016/j.tins.2013.01.005
2. Cryan JF, O’Riordan KJ, Cowan CSM, et al. The Microbiota-Gut-Brain Axis. Physiol Rev. 2019;99(4):1877-2013. doi:10.1152/physrev.00018.2018
3. Kelly JR, Borre Y, O’ Brien C, et al. Transferring the blues: Depression-associated gut microbiota induces neurobehavioural changes in the rat [published correction appears in J Psychiatr Res. 2016 Aug;80:48]. J Psychiatr Res. 2016;82:109-118. doi:10.1016/j.jpsychires.2016.07.019
4. Strandwitz P. Neurotransmitter modulation by the gut microbiota. Brain Res. 2018;1693(Pt B):128-133. doi:10.1016/j.brainres.2018.03.015
