Question: there are over 200 mental illnesses so how can you tell the differences in every single one of them? Surely this would take years and years to learn

Laura Fisk answered on 17 Jun 2019:

Hello! Sorry for the delay – my computer deleted my (really long, perfectly crafted 😉 ) answer 🙁 So here I go again!
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There are two main manuals of criteria (types of experiences) that are used to give mental health diagnoses: one for the US and one mainly developed in Europe for researchers. The manuals are basicallly made by researchers and experts in the fields who look at some research and go on some of their clinical experience. They gather together lists of different experiences (sometimes called ‘symptoms’) together and give them a label, e.g. ‘depression’, ‘schizophrenia’, ‘obsessional compulsive disorder’ etc
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Like you’ve pointed out, there are a lot of combinations of criteria and lots of labels. Also, there’s an additional challenge with these manuals in that they’ve changed a fair bit over time – so there’s not really any static (fixed) criteria for any single diagnosis. This makes some people (like me) question how helpful the diagnoses are – if they change, what do we think we are talking about from year to year? Are we talking about the same things? Another problem is that some of the criteria and labels have a political side to them, even – so what does it even mean to be ‘ill’ – what if the government is just trying to control you?
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HOWEVER! Because whatever the legitimacy of the diagnoses, what they’re describing (or alt least trying to describe) is humans. And we all work in pretty similar ways, on one level. This means we can spot patterns, make predictions about the kinds of things that might happen together – so suddenly you’re not learning 100 different criteria, youre learning five ‘sets’…
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Here’s an example: If something is affecting my mood, Imy energy and motivation levels will be affected –> my sleep will be affected –> sleep works on a simlar system as appetitie, so that’s mucked up –> upset appetite usually means upset tummy, skin, hair and other stuff –> anxiety
Now, I can call this depression, but I also only need to know one bit of that chain and I can work out the rest that’s likely to be in play
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Another thing is that beyond these general criteria, some specific things are more uncommon and therefore more informative – it’s like, if they’re present for a person, they act as a big signal as to what’s going on.
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An example of this is ‘seeing things other people can’t see’. Now, this does come up for people in all kinds of contexts, but because I know it’s relatively unusual I’m at least expecting the person to be experiencing stress. Now I can think of things that I want to rule in, or rule out – if they’ve just had a baby I might be looking at ‘puerperal psychosis’ and if they haven’t I might want to look for ‘schixophrenia’ criteria. Depending on the clinician’s experience, they might need to look up specific criteria – or they might just have remembered them with practice (using them a lot).
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So basicaly, yes there are a lot of diagnoses but no you don’t have to learn allll the critera 🙂

he thing is, we’re all humans with pretyy similar bodies, at the end of the day. This means similar things often go together, and this means it’s easier to spot patterns. What I mean by this is, if someone is stressed their ‘basic body needs’ will be the first thing that gets thrown out of kilter: sleep – appetite – tummy. So, many diagnoses include something to do with this          ‎‏‪‫‬‭‮