If you’ve ever had to “trust your gut”, you know just how strong the connection between the mind and the body is. When you sense that knot in your stomach and the nervous butterflies start, it can definitely feel as though you have a brain in your belly, but that gut feeling is more reliable than you think.
For years, scientists have endeavoured to understand the mysterious relationship between the gut and our mind. It goes beyond emotions; there is even accumulating evidence to suggest a connection between our gut health and mental state. A decline in one often worsens the other, so why aren’t they being treated as one?
As the field of psychedelic medicine begins to flourish, perhaps the mind-altering effects of these drugs could stretch to our second brain.
The microbiome controls the mind
Before we delve into the mysterious relationship between our gut and mental health, let’s go over the basics. What is the microbiome, and why is it so important?
The term microbiome refers to the collection of microorganisms that colonise our body, consisting of bacteria, archaea, viruses, and fungi. The diversity of our gut microbiome, or the balance of our “good” and “bad” bacteria, is a major predictor of our health and wellbeing. It has even been shown to influence our brain function and behaviour.
Our gut bacteria actually help to regulate the production of serotonin in the digestive tract – 95% of our body’s serotonin, in fact. Not only is serotonin involved in modulating various gastrointestinal (GI) processes, but it is also a crucial regulator of our mood, cognition, appetite, sleep, and immune health. Hence, it is often referred to as our “happy hormone”.
The gut and the brain are, therefore, inextricably linked. This connection, termed the gut-brain axis, refers to all of the hormonal and neurological pathways that tie the brain to the gut, mediated by the vagus nerve. It’s a two-way street; mood disturbances can throw off our gut health, just as imbalances in our microbiome (known as dysbiosis) can hinder our brain function.
The gut-brain axis is a fascinating relationship that is often overlooked. For instance, it’s not uncommon for people with irritable bowel syndrome (IBS) to experience anxiety and depression, but since the gut isn’t necessarily the obvious culprit for poor mental health, this can make it hard for people to pinpoint the root of their problems.
Intriguingly, it has also been noted that selective serotonin reuptake inhibitors (SSRIs), common forms of antidepressants, offer therapeutic benefits in various GI disorders. This has led some researchers to speculate that emerging mental health therapies could also help to support our physical health and wellbeing – and this is where psychedelics come in.
A psychedelic trip – can you stomach it?
Research into psychedelic drugs is experiencing a renaissance, and evidence in favour of their use in treating countless mental health conditions is piling high. Psychedelic-assisted therapy is a revolutionary approach to mental health. It helps patients to address the true source of their problems which, unlike leading drugs, prioritises healing from within.
There is a fascinating crossover between the conditions being studied and treated with psychedelic therapy and those associated with dysfunctional gut health. Depression, anxiety, and post-traumatic stress disorder (PTSD), among others, have all been linked to microbial dysbiosis in the gut. They, too, appear to respond to psychedelic therapy. So, could the gut play a role in a psychedelic trip?
Most people with experience of using psychedelics will say, without a doubt, yes. Abdominal discomfort, nausea, and even vomiting are surprisingly common features of the psychedelic experience. In ayahuasca ceremonies, this is a crucial element of the healing process, where so-called “purging” is seen as expulsion of trauma or negativity.
It is thought that the gastrointestinal side effects of psychedelics are due to their ability to activate serotonin 2A (5-HT2A) receptors, the same receptors responsible for the hallucinogenic effects of psychedelics in the brain.
So it’s clear that psychedelics do something to our gut. The extent of exactly what isn’t yet known, but “if, in fact, psychedelics are having an impact on good bacteria or bad bacteria [in the gut], then that impact—in either changing the numbers or changing the function of those bacteria—could have a positive impact on anxiety, depression, or GI disorders,” Jane Foster, a microbiome researcher, tells Vice.
Healing from within
Scientists have begun to investigate whether this gut-brain connection could be enhanced using psychedelics. Would it be possible to heal the gut through the mind, and vice versa?
Researchers Dr Kate Pate and Dr Christopher Lowry believe so. They are working with the Heroic Hearts Project to understand the effects of ayahuasca ceremonies on the microbiome and how this could influence PTSD symptoms in veterans.
Previous research has highlighted a substantial link between inflammation and PTSD. The exact mechanisms are not yet known, but Pate and Lowry suggest that stress and trauma reduce the diversity of the microbiome, making the gut more vulnerable to pathogens and, thus, more likely to become inflamed. Gut inflammation, also known as “leaky gut”, can cause bacteria to enter the body and trigger systemic inflammation.
There is also evidence to suggest that inflammation can exacerbate PTSD symptoms, suggesting that gut dysbiosis is both a cause and consequence of poor mental health. Although this hasn’t been tested experimentally, Pate and Lowry believe that “an altered microbiome may play a role in the transformative effects of ayahuasca.”
Another researcher, Dr Kim Kuypers, has offered a similar theory. She proposes that the positive effects seen with microdosing psychedelics could have more to do with the gut than previously credited, suggesting that “low doses of psychedelics induce their effects via alterations in the microbiome and related pathways to the brain.”
Currently, there is no experimental evidence to support this theory, but Kuypers’ paper highlights a need for further research into the mechanisms underlying the therapeutic benefits of psychedelics. Perhaps the gut-brain axis is more involved than we think.
There are far more questions than answers when it comes to psychedelics and gut health. It may be that these drugs can directly reduce inflammation through 5-HT2A receptor activation in the gut and, in turn, improve symptoms of mental health conditions. Or, alternatively, the improvements in brain function seen with psychedelic therapy could have positive downstream effects on gut health. But until the underlying mechanisms are fully investigated, the details of the gut-brain relationship remain a mystery.