The false dichotomy of the mental and the physical

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A hidden pandemic has gripped the world. More than a billion people are sick. 1 It spreads with no agent nor pathogen. No vaccine nor cure exists for this pandemic and no single factor can determine the outcome of this disease. Some people deny having it. Some people will die from it. It is one of the leading causes of disability. 2

It sounds like zombie fiction, but this is the truth for mental illnesses. Anxiety and depression are the most common types with severe cases leading to suicide, one of the biggest killers of 20-35 year olds. Governments are criticised for their lack of action to mitigate this problem with median government spending at around 2% of their health budgets. 3 This is compensated with people-powered movements pushing for awareness and prevention. It seems unavoidable nowadays to scroll through social media without seeing a post about mental health awareness or something adjacent. But the reverse is also true; the prevalence of mental illnesses led to fetishizing tropes such as menhera girls, a Japanese subculture that sports self-injury scars with pride.

Regardless, the image of mental health often evokes a gray picture of a young woman (women are more severely impacted by mental illness) with razor blades close at hand or a hand shoved down their throat. This is true with menhera girls. Other popular depictions are less obvious. An example is Hannah Baker, a highschooler who committed suicide in the problematic TV show 13 Reasons Why.

Fictional character Hannah Baker from 13 Reasons Why. The show was a major source of controversy due to Hannah’s very explicit suicide scene. The scene was edited after release. 4 © Netflix

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You might have heard this term: “mental illness is invisible”. Invisibility is an apt term. Self-harm scars can clearly indicate some issues converging towards mental illness. Its absence, however, does not eliminate the possibility that some mental illness does not exist. Hannah Baker wears long sleeves that conceal longitudinal scars, and the picture clearly shows a young woman and not much else. No cuts mar her face, and her face is remarkably flushed with no hints of paleness. There are no pustules or missing limbs. Removed from any context about the show, she looks remarkably and paradoxically healthy. Physically, that is.

Reality has its paradox. Mental health is an illness, yet it doesn’t have any clear, definable cause. You cannot test it with Koch’s postulates; it is impossible to accurately measure the depression and anxiety levels of a test organism. 5 Yet there are medicines ready to treat mental disorders. At the same time, some treatments are fickle and can vary in effectiveness from person to person. SSRIs, the most common antidepressant prescription, can both increase and decrease suicidal tendencies. 6 How come?

You can argue that mental illnesses are mental illnesses. They exist separately from physical illnesses and that usual methods designed to diagnose and treat mental illnesses don’t apply. You could take this argument one step further, say that the actual cure for mental illness is to “live well” and nobody who takes medicine ever needed them anyway. If it exists outside the realm of the physical, why should it follow its rules?

But to separate the mental and the physical requires a degree of faith. It assumes that feelings operate separately from the brain, a physical organ made of flesh. It assumes that feelings come from the soul, which is an entirely different theological debate. That explanation does not satisfy scientists so they conducted studies to try to find the pathophysiology (the biochemical or pathogenic cause) that underlie mental illnesses like autism, depression and anxiety.

One could argue that you could cure mental illness through living well and maintaining discipline. This claim could be true, but its implications must be evaluated. Are you still assuming it isn’t a “real illness” hence it could be easily “taken care of”? You must reframe your thinking if you assume being sated and happy immediately cures mental illness, but you must also reframe your thinking if being sated and happy doesn’t affect mental illness. Living well might include exercise, but exercise doesn’t improve mental health because it makes you happier, it improves your mental health because it affects your biochemical processes. 7 Eating well doesn’t just make you happier, it ensures you obtain the nutrients you need, and this is especially important in depression which is linked to vitamin deficiencies. 8

A common theory that people have considered, aside from vitamin deficiencies, is that most mental illnesses are dysregulations of certain hormones in the body. If dopamine is the happy hormone, depressed people must be lacking it. The dopamine theory lacks some consistency with depression, 9 but irregular adrenaline seems to have an effect on people with PTSD. 10, 11 Anxiety seems to be related to cortisol; those with higher risks of anxiety shows similar patterns when their bodies are releasing cortisol. 12

This seems to be the working theory and is the basis of many medications nowadays, but the variance in the effects seem like our theory isn’t enough to cover the extremely broad subject of mental illnesses. What other factors are at play that make this theory work sometimes, but not always?

You’re not alone

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It may comfort a person with depression to tell them they aren’t alone. They aren’t alone in the context of other people experiencing depression, in the context that they still have people around them who care about them. It’s true, you are never alone. But not in that sense. You have trillions of living things dwelling inside your gut, numerous different species who call your insides their home. These could dwell there silently and not have any significance to you, but they could also help you digest foods that are difficult for you to digest. Or so you think.

The gut microbiota’s recent place in research is a realm of intrigue and adventure. Identical twins could have an identical set of DNA but vastly different species of gut microbiota. Whether you were born through a caesarean section or not will affect your gut microbiota. How long you sleep and when you sleep matters too. Most importantly, it is also affected by diet.

The gut microbiota might seem like a farfetched case compared to our previous discussions about mental disorders. But the gut plays a bigger role than you think. As bacteria, fungus and viruses go about their microscopic lives, they inadvertently release chemicals akin to sweat that naturally rests on human skin. These chemicals can communicate with the immune cells in the body. 13 In fact, it communicates with the human’s “second brain” which is the enteric nervous system, an entire nervous system located in the abdomen. 14

While it makes sense that there is a nervous system dedicated for digestion, it starts to sound like fantasy that the gut microbiota could influence the nervous system and cause mental illnesses. Yet, this is a possibility worth exploring in science that does not yield empty results. Numerous studies have proven that the microbiota are linked to depression, anxiety, autism spectrum disorder (ASD), schizophrenia, bipolar disorder and ADHD. 15 People with depression have less Bacteroidetes in their gut while people with bipolar disorder seem to have four times less Clostridiaceae that ferments carbohydrates compared to people without bipolar disorder. There are more Actinobacteria in people with ADHD. 16

To some scientists, they can’t agree whether the microbiota caused the illness or the illness caused the microbiota. It may seem a more obvious conclusion that the latter makes more sense. Yet, in the case of ADHD, the microbiome seems to be capable of producing a component that allows for more production of dopamine. 17 Additionally, when you transfer the microbiota content of depression to a healthy organism, they start to exhibit depression-like symptoms.18 It seems that the obvious conclusion isn’t so obvious after all.

Sometimes you’re born with it

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You’ve heard of this on TV: “I got his DNA from his hair!” But what is DNA? A lot of people can’t answer beyond it being something unique that everyone has. Scientifically, DNA is a macromolecule. It is a small molecule that is large by chemistry standards. Meaning, you can’t see it with your naked eye, but it’s made up of millions of elements that is a mixed bag of carbon, nitrogen, hydrogen and oxygen. Every living part of your body has this, and what’s even more great is that it contains the instructions for your body to do the things it needs you to do. You have genes, short instructions, who will tell your body things like it should ensure your eye color is brown or another color.

You cannot change your genes; it is inherited to you from your parents. Genes seem to determine a lot of physical characteristics, but a lot of mental characteristics seem to have a link towards genes as well. This might seem deterministic. If my parents have given me the genes for introversion, does that mean I’m doomed to remain tragically a hermit? It sounds like genes remove any sort of individual agency. “My genes made me do it!” says a man in court during trial for murder. Luckily, there are more factors at play than just dealing with the genes you were dealt with. Genes could be silenced or overexpressed, depending on the situation and environment. Obviously, genes for growth wouldn’t be active throughout your entire life and at some point after puberty, your height will remain tragically the same.

A lot of diseases have been attributed to genes. Diabetes, for example, has been attributed to hundreds of seemingly unrelated genes who, when malfunctioning, seems to increase the chances you develop type 2 diabetes. 19 If we want to treat mental illnesses the same, it appears that it is possible to attribute some genes to mental illnesses.

You may have heard this piece of interesting news: the man who discovered he was a psychopath 20. Psychopathy has long retained its reputation in media as evil, irredeemable villains beyond the understanding of guileless protagonists. In reality, psychopathy in a clinical context refers to “antisocial” behaviour from a lack of empathy to egocentric traits. While these traits might seem horrifying, these traits aren’t damning, as James H. Fallon, the neuroscientist who found he was a psychopath, leads an entirely normal life. That is, if normal includes starring in numerous documentaries and obtaining an acting role in Criminal Minds.

James H. Fallon, a neuroscientist who discovered his genetic disposition towards psychopathy. He proceeded to star in TV shows talking about his discovery. He has no criminal record. © IMDB

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While Fallon admitted to some low empathy behaviour, he has no inclinations towards violence. He attributed this to a happy childhood and supportive environment, which destroyed any potential of genetic determinism taking hold of his life.

Regardless, while genetics doesn’t always determine that you must definitely have mental disorders, it does change the odds of it. Autism, for example, is associated with 800 genes, and 50% of ASD individuals have one of these: another syndrome that may cause their autism, a single gene being mutated, or a problem with their chromosomes (that is, either a huge chunk of DNA is missing or a chunk of DNA keeps repeating itself through some error). 21 Meanwhile, ADHD has a very high heritability of 74%, meaning it has a 74% chance of being caused by the individual’s genetics. 22 Different types of depression can appear when genetics, environment, and the brain you were born with, encounters problems and the balance they maintain is disrupted. 23

The role of… immunity?

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Genes often are given names that sound like code names. NCKAP1, for example, is a gene that helps regulate development of neurons. Apparently, a mutation, or a change, in NCKAP1 that affects its function, can cause autism-like symptoms to appear. 24 Yet, if you were to search NCKAP1 on the internet, a lot of it is about its role in cancer. What’s more, you might find something about the other function of the gene, which is to modulate, or control, some aspects of the immune system.

A very controversial claim was made once, and would affect paranoid mothers forever everywhere: the claim that vaccines cause autism. The paper that first published this was retracted, partly due to the fear it nurtured towards vaccines, but mostly because the paper had a huge conflict of interest due to the writer receiving funding from parents who were in the midst of suing a pharmaceutical company. He intentionally selected children to manipulate the results of the study. 25

Vaccines work by inserting a very weakened version of a disease agent into a patient, whose body will recognise and allow the immune system to be trained to be able to prevent diseases when encountering truly dangerous diseases. At its core, the immune system’s entire schtick is to recognise and eliminate. Errors in the immune system could be something like it being too weak to fight off infections, or it being too strong that it starts fighting the body instead.

While the paper is retracted, there still exists a link between the immune system and mental illnesses. Depression was linked to the body’s response to infection. 26, 27 Surely, it makes sense evolutionary-wise: first, your body is infected with disease; next, you develop depression with a higher chance of isolating your body from other human contact to prevent infecting other people and spreading the disease.

But what about other mental disorders like schizophrenia? Still, another immune dysfunction. A study replaced a schizophrenic patient’s bone marrow and the patient was cured from schizophrenia. The bone marrow is the maturation site of a lot of immune cells. This means that you could treat schizophrenia by treating the immune system. 28 Autism was also linked to a dysfunctional immune system, and studies proved this from taking blood and fluid from the spine. 29

So, what is the conclusion?

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Is it the gut, the genes, the immune system, or the environment? In the end, it’s all of them. Depression, for example, is caused by all four. 30 Meaning, a lot of things had to go wrong for it to develop. This article doesn’t even cover how depression increases for people who have heart disease, 31 or how sex differences can cause different symptoms of ADHD to manifest and may or may not be due to sex-specific hormones. 32 The field of mental illnesses is rapidly developing, and to dismiss all mental illnesses to be anything below a systemic illness that involves the physical body is graciously uninformed. There is no separation between the mental and physical, all of that is a false dichotomy.