The Mental Health Workers’ Guide part 4:

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The meaning of psychiatric Diagnoses

One of the most common concerns among social care workers, at least those I meet is around diagnosis. There are so very many different psychiatric diagnoses, all with their own particular symptoms and they seem almost impossible to remember.

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I can sympathise with that view – there really are a lot of diagnoses and the differences between them sometimes seem so very subtle that it’s hardly worth mentioning at all. However – that doesn’t need to be such a problem in social care.

Support workers aren’t diagnosticians and they don’t need to be able to fit everyone they work with into the particular boxes of psychiatric diagnosis. It’s enough to know what the service-user’s actual problems are without worrying about pigeon holing them. After all – there really is much more to life than diagnosis.

So here’s a breakdown of what really matters in psychiatric diagnosis.

The term ‘diagnosis’ comes from Greek. It’s made up of two words:

1.       Dia – through

2.       Gnosis – knowledge

Diagnosis means ‘through knowledge’ and yet we know much less than we’d like to for sure. In fact there are those who argue that diagnosis is little better than useless in mental health care and should be replaced by a different system known as ‘formulation’ instead. This is because whereas diagnosis seeks to place sufferers and their conditions into predefined ‘boxes’, formulation seeks to construct a new explanation for each individual regardless of the experiences of other people and the ‘boxes’ they may have occupied in the past.

Perhaps the biggest criticism of diagnosis in mental health care is based upon the established purpose of diagnosis. It is intended to:

1.       Predict outcome;

2.       Inform treatment.

In the case of diseases like Alzheimer’s dementia or Parkinson’s disease diagnosis can (to a greater or lesser extent) fulfil both of these promises. In the case of ‘Schizophrenia’ or ‘Brief Psychotic Episode’ it seems far less effective and in the opinion of many far less plausible too.

It’s important to be clear about what this means in practice. There’s a set order (a syntax) to psychiatric diagnosis and it really only works in one direction. This is different from many other sorts of diagnosis, the diagnosis of physical illness for example. That’s because whereas physical illnesses tend to be diagnosed ‘through knowledge’ of measurable physical processes with very specific, known (or at least likely) and predictable specific effects, psychiatric diagnoses tend to be based upon ‘clinical judgement’ with little or no physical tests available to support them.

Psychiatrists don’t rely upon measurable evidence to support their diagnosis and so they can’t really say for sure that one symptom will follow another. For example…

The physical diagnosis of COPD (Chronic Obstructive Pulmonary Disease) is diagnosed using specific tests that show that a person’s lung function is impaired. The inevitable result of significantly impaired lung function is breathlessness when exercising. So, because of this measurable condition and the inevitability of breathlessness we can reasonably say…

“Of course John gets breathless – he has COPD”

We can say this because we have excellent evidence of impaired lung function and because we know what happens to respiration when people with COPD exert themselves. We have good, testable information about the causes ranging from oxygen saturation levels in the blood to peak flow metering of the breath itself to name but two. We know what we’re looking at in other words.

Psychiatric diagnosis is different. It isn’t usually based upon blood tests or sophisticated scans. Instead the psychiatrist takes a history, observes the current ‘presentation’ of the patient and then makes a diagnosis based upon how closely the person’s ‘symptoms’ match the descriptions in the psychiatric diagnostic manual.

This means that diagnosis only shows what ‘symptoms’ are already apparent – it can’t predict other symptoms that aren’t already there. This means that we can only say something like:

“John has a diagnosis of schizophrenia because he has visions.”

We cannot say:

“Of course John has visions. He has a diagnosis of schizophrenia.”

Not everyone diagnosed with schizophrenia has visions. So the symptoms might explain the diagnosis but the diagnosis can’t explain the symptoms. It’s just a name, a label and names don’t explain things – they simply classify them.

For example, on my office wall I have a large clock. I know it is a clock because it has the observable characteristics of a clock (hands that rotate, a numbered face and it ticks). However naming it as a ‘clock’ doesn’t tell me anything about how it works. I am no closer to understanding the intricate mechanisms of the various cogs and springs inside the clock just because I know what to call it.

Many psychiatric diagnoses are just like that. We are no closer to understanding the workings of schizophrenia just because we can name it. That’s why we must be careful to let symptoms explain the diagnosis but not to delude ourselves into thinking that the diagnosis explains the symptom.

The ‘syntax’ of psychiatric diagnosis

Observe symptoms

2 Compare symptoms to the diagnostic manual

3 Find the most likely ‘fit’ in the manual

4 Name (diagnose) the set of symptoms

5 Decide treatment (within accepted protocols)

6 Predict outcome (with varying degrees of accuracy)

Generally speaking we can only go one way with psychiatric diagnosis. It doesn’t usually work well ‘in reverse’.

The symptoms explain the diagnosis

The diagnosis does not explain the symptoms

But diagnosis isn’t entirely useless. My own view is that it is too reductionist. Diagnostic psychiatry reduces people to component parts to be ‘fixed’ rather like a mechanic working on an engine. Diagnosis has its place although, like many other people working in mental health services, I’d welcome a more widespread use of psychological formulation alongside the ‘boxes’ of traditional psychiatric practice.

In the simplest terms mental disorder is really only a combination of three types of symptom:

•        Anxiety – physical and psychological arousal

•        Depression – physical and psychological dearousal

•        Psychosis – hallucinations, delusions and thought disorders

All mental disorders (except the dementias which also include memory and orientation problems) are made up of combinations of these three types of experience or people’s vulnerability to them.

Personality disorders are diagnoses based upon the way people usually think and behave and upon their susceptibility to anxiety, depression and psychosis.

In the next few episodes we’ll look at the three types of symptom in turn.