I believe in diagnosis but the DSM is just a door-stop

About a month ago, the Applied Psychology Department of Canterbury Christ Church University asked me to write a guest piece for their blog. After much rumination and multiple re-hashes, it was posted earlier this week. They usually hold a fairly anti-diagnosis, pro-lived experience position, so I was glad they agreed to let me discuss how I think that in the real world, diagnosis isn’t all about DSM-5 and symptom counting. The original piece, complete with a thoughtful string of comments, can be found here.

The heat from the release of the “psychiatric Bible” (DSM-5) is thankfully simmering down. In recent months, you couldn’t throw a metaphorical brick on Twitter without hitting someone who had a strong opinion and wasn’t shy of sharing it. I found this debate stimulating, frustrating and eventually repetitive. Rarely however, did I find it clinically relevant.

There may be a number of reasons for this. For one thing, DSM-5 is an American book; we use a different classification (ICD-10) here in Britain. Also, I currently work in an area of psychiatry that deals heavily with an illness that DSM doesn’t have a definitive role in, namely dementia. But mostly, I wasn’t too bothered because, to the probable surprise of non-medics and the public, most psychiatrists don’t really care about the finer points of classification.

It’s not that psychiatrists don’t believe in the merits of diagnosis. Both I, and the vast majority of colleagues I’ve encountered, see large benefits in labelling people. I think it provides a useful conceptual framework, a way of thinking about someone, helping someone, and researching common types of suffering. And it’s not that I and many colleagues are quacks, giving whatever wild and personally favoured diagnosis we feel like, without thought for inter-rater reliability. I’m aware of the controversies about diagnosis, and the harms that it causes when we get it wrong. However, these are not the reason why many psychiatrists don’t have a large amount of time for DSM.

No, the reason it doesn’t get much attention from us is because most diagnoses are pretty clear. Patients usually fit quite neatly into the large, intuitive boxes for mental distress that we’ve already had for years. If you’re really unhappy, we call it depression. If you’re really happy, we call it mania. If you’re hearing voices, are paranoid and believe utterly strange things, we call it schizophrenia. These are the broad descriptions that we see standing out in our patients, and it’s these that we use in our day to day careers. Whatever tweaks are made to the classification of things like depression aren’t going to change anything. Really sad people will still be depressed.

The small print doesn’t seem useful to us a lot of the time. ICD-10 states that to have a moderate depressive episode, you need to have at least two key symptoms (low mood, loss of interest and enjoyment, and increased fatigability) plus at least three other symptoms (loss of appetite, poor sleep etc) but to have a severe depressive episode, you must have all three key symptoms and at least four others.

This clearly isn’t how depression works in the real world, and psychiatrists, who are more interested in the amount of suffering than the number of symptoms, recognise this. If a patient feels so bad they might try to kill themselves, they’re admitted to hospital whether the book says “moderate” or “severe”. If they’re suffering so much they might lose their friends or marriage, we’d advise an antidepressant regardless of their ICD-10 code. This is a very different thing, however, to arguing that a diagnosis is useless and unreliable, or that depression isn’t “real”.

The endless media reports of psychiatrists ‘labelling grief as mental illness’ were frustrating for me. I think the Daily Mail believes we’ve started picketing funeral homes, with anti-depressants in hand. The truth of the matter is that the expanded definition of depression (which makes it possible to diagnose depression within 2 months of the loss of a loved one) changes nothing in our clinical practice. If you were suffering enough to need drugs before, you still will be. GPs won’t suddenly send us vast swathes of bewildered people who now fit slightly inside DSM criteria for treatment.

Being less reliant on strict classification has both good and bad consequences. It allows us to cast aside our textbooks to see the person, while still maintaining a workable overarching structure with which to conceptualise their distress. It hopefully makes things more personable for the patient, who is told he has bipolar disorder and he’s currently manic, not that he has ‘F31.1: Bipolar affective disorder, current episode manic without psychotic symptoms’.

But we don’t use this simple, loose method of diagnosing all the time. Many specialist services, who deal with problems like autism and ADHD find it useful to stick closely to the classification, usually because it is well grounded in research and useful in deciding whether someone truly does have the disorder or not. Likewise, researchers will classify their participants tightly, so we can all tell who they’ve been studying.

And yes, sometimes flicking through ICD-10 has helped me. I remember one young man who puzzled with his strange behaviour, which included barking at the moon with a bowl on his head and describing the vibrations in parts of his brain. Despite his actions, he seemed quite attached to reality. It wasn’t until I reacquainted myself with the criteria for schizotypal personality disorder that I began to understand him better.

So, although the finer points of diagnostic classification can be useful, the vast majority of the time psychiatrists have far more pressing concerns than which subgroup of a subgroup someone falls into, like how bad someone is feeling and whether they need help.

The fact that the public thinks we sit in our offices, thumbing through DSM, ticking off symptoms to reach a diagnosis, is both hilarious and worrying.

ICD-10s are propping open doors, steadying wonky tables and gathering fine coverings of dust worldwide. The assertion that we’re devoted to these tomes as our ‘Bibles’ is just plain nonsense.

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