Microbiota, Psychotropic Drugs, and Altered Minds


Over the past few years, it has become glaringly apparent that the community of creatures we call the gut microbiome can affect what we fondly think of as “our” minds. The bugs are impacted by, and react to, every medication that we ever ingest. They crank out chemicals that affect our brains and bodies as effectively as pharmaceuticals. Just like some street drugs, the bugs can push us into doing insane things, against our own best interests. There is a lot going on in our digestive tracts.

A 2012 report spoke of how the microbiota could “contribute to diseases ranging from inflammation to obesity” and added that brain function and behavior were also involved. It named anxiety, mood, cognition, and pain as areas susceptible to influence.

Psychotropic drugs, like atypical antipsychotics, were recognized as having undesirable side effects — such as promoting obesity. New discoveries about the microbiome’s power led, among other things, to speculation about whether the bugs could mitigate the harmful aspects of pharmaceuticals.

Speaking of psychoactive drugs, in the same year a paper was published on “how the endocannabinoid system, intestinal microbiota and the brain-gut axis are involved in the regulation of energy balance and the development of obesity-associated systemic inflammation.” N.L. Cluny, R.A. Reimer, and K.A. Sharkey made this bold statement:

Through direct and indirect actions throughout the body, the endocannabinoid system controls the development of obesity and its inflammatory complications.

The bugs collaborate in producing chemicals that can alter the brain’s biochemistry just like meds prescribed for patients with mood, anxiety, and depression disorders; or, for that matter, party drugs and psychedelic substances taken for inner exploration. LSD can affect how people feel, think and act — and so can the chemicals produced by the bacteria in our intestines. Jan Birch wrote:

The same substances used by our neurons to communicate and regulate mood, like dopamine, serotonin and gamma-aminobutyric acid (GABA). These, in turn, appear to play a function in intestinal disorders, which coincide with high levels of major depression and anxiety.

Just like a drug, “these bacteria can influence our perception of the world and alter our behavior.” In the same way that a drug experience can have a lasting effect for good or ill, researchers have shown that negative events like childhood trauma, combined with actions of the microbiome, can have far-reaching and even life-long consequences.

Susie Neilson related how a study of students with Irritable Bowel Syndrome and healthy volunteers discovered that…

[…] our guts may harbor evidence of difficult life experiences many years after the fact, changing everything from how we digest food to how we process stress. In fact, these changes in our “second brain” may substantially alter the structure of our first, creating a feedback loop between the two.

Dopamine and serotonin are mood-altering drugs manufactured by our own bodies. That’s the good news, but the bad news is who is in charge of production. Often, the microbiota run the show. They are so sneaky, they will change our taste buds to like the things that they like.

Consider for a moment how much we cherish our individuality, which is made up of our own particular combinations of feelings, thoughts and actions. Jane Birch says:

Intriguingly, when gut bacteria is swapped between two different strains of mice, it can lead to complete personality changes. According to microbiologist Mark Lyte, “If you transfer the microbiota from one animal to another, you can transfer the behavior.”

Your responses and feedback are welcome!

Source: “Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour,” NIH.gov, October 2012
Source: “Cannabinoid signalling regulates inflammation and energy balance: the importance of the brain-gut axis,” NIH.gov, 2012
Source: “Discovering the Word of Wisdom: Food Cravings, Obesity, Mood, and Our Gut,” LDSmag.com, 02/22/16
Source: “Gut Feelings–the ‘Second Brain’ in Our Gastrointestinal Systems,”
ScientificAmerican, 05/01/16
Source: “A Traumatic Experience Can Reshape Your Microbiome,” TheCut.com, 06/01/17
Photo credit: jrduboc via Visualhunt/CC BY

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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