If I asked this question to a random passer-by in any city in the western world I would probably get a mix of different answers but possibly with an overall  consensus that might be something like: “a disease of the mind”, a “problem with the brain” or a “non-physical illness”.

Thinking of a mental illness as just a disease of the mind or brain though means that it would have to include things such as brain tumours, strokes, or Alzheimers disease, each of which is not considered to be a mental illness by the medical professionals.

So let’s have a look at what these “professionals” say:

Wikipedia, that bastion of collective knowledge gives the definition as:

“A mental illness is a condition that impacts a person’s thinking, feeling or mood and may affect his or her ability to relate to others and function on a daily basis. Each person will have different experiences, even people with the same diagnosis.”

The Mayo Clinic gives it as:

“Mental illness refers to a wide range of mental health conditions — disorders that affect your mood, thinking and behavior. Examples of mental illness include depression, anxiety disorders, schizophrenia, eating disorders and addictive behaviors.”

These are really just as vague as the answers I hypothetically received from my hypothetical passers-by.

I mean having a common cold can affect my mood and my behaviour but is certainly not considered a mental illness.

My point here, albeit made a little bluntly, is that the idea of a mental illness is really just a loose fitting label given to problems that affect the mood, thinking, or behaviour of a person, but which cannot be characterised as anything else. In other words it cannot be tested through a physical process, as once it can it then becomes a physical problem.

This leads us to the realisation then, that there are no physical tests for mental illnesses at all (by definition) and therefore all diagnoses can only be made on anecdotal evidence and observations alone.

I think Dr Thomas Szasz, professor Emeritus of psychiatry at new York Medical school put it best when he said:

“There is no blood or other biological test to ascertain the presence or absence of a mental illness, as there is for most bodily diseases. If such a test were developed…then the condition would cease to be a mental illness and would be classified, instead, as a symptom of a bodily disease.”

So when we get down to the nuts and bolts of it all, the only real difference between physical and mental illnesses is that there is no way to test for a mental illness.

It is true that no blood test, scan, genetic markers, or chemical imbalance has ever been found for what we describe as mental illnesses and that is why they are still considered to be mental illnesses. But does that mean there isn’t one out there somewhere?

I mean, only 100 years ago we had no way to test for heart disease and relied on observations of the patient and the patient’s own description of the symptoms. Today of course we have a battery of tests we can do from an EKG, to cholesterol tests to the CT scans of blood vessels. Now we can very accurately diagnose and often even predict heart disease, but 100 years ago it was all a bit of a crap-shoot.

Who’s to say then that in 100 years time, we won’t have found tests that can diagnose or predict our mental illnesses. Does that mean they will stop being mental illnesses? Well yes it does. As soon as we discover a “physical” test, then the illness must be considered a symptom of a physical problem.

Once there is a blood test for schizophrenia, or a CT scan for depression, then these things must become symptoms of physical illnesses just like brain tumours or heart disease.

This boils down then to show our elephant in the room, that all mental illnesses are just physical illnesses that have yet to be tested or diagnosed properly. It is dangerous to assume I think that just because an illness is written in the Diagnostic and Statistical Manual of Mental Disorders, that a physical cause or test will never be found for it.

Thankfully even though the official stance in psychiatry is still that mental illnesses and physical illnesses are distinct and separate and “never the twain shall meet”, there is a growing movement towards the idea that maybe mental illnesses are just physical illnesses of the brain that have not yet been properly diagnosed.

I certainly think this is the case and I think we have done a disservice to mental illnesses by not treating them as physical issues and therefore not putting our collective weight behind finding physical cures.

This has undoubtedly been the case with anxiety and I think it is only a matter of time until the medical establishment recognises the roles that physical processes play in General Anxiety Disorder.

Just talk to any general anxiety disorder sufferer and I bet you they talk about physical or emotional symptoms that occur without any “crazy”thoughts.