Abnormal Psychology 3018 Definition and Classification II

Necessarily monothetic and has a unique set of essential or defining features/conditions.

… not be the kind that it is.

Because those disorders do not have unique sets of essential or defining features.

In truth, they just function as linguistic markers in everyday language that refer to a polythetic concept.

A scientific definition is not:

1. an operational definition.

2. ostensive.

3. a description of the: a) conditions process/procedures that CAUSED the disorder, b) the signs/symptoms of the disorder, c) the effects or consequences of the disorder.

4. the functional purpose of the disorder.

5. a description of the (so-called) measurement of the disorder.

6. scientific classification.

Well, what an operational definition is depends on who is teaching you. But the standard take is either the steps an investigator must take to measure/manipulate a variable OR a manual of instructions.
But it is not a genuine definition, it is just a description of a procedure.

Well, ostensive = ‘to directly demonstrate’ or ‘point to’. Pointing to something is not describing any essential defining features.
Pointing to an example of X is not to define X.

A scientific definition is not a description of:

a. the conditions/processes/procedures that caused X (what caused something should not be included in the definition).
b. the signs/symptoms of X are not X (e.g., oxygen and hydrogen are not water).
c. the effects or consequences of X.

Well, logically, you can talk about the function of a shoe but that is different to what the show actually is.

Measuring something, or finding the amount of something is NOT what that something is.

Definition does not equal classification, these concepts are often confused in psychology.

Well, what is it to classify? We are constantly classifying according to our knowledge, needs and interests (e.g., my interest in alcohol means that I classify gins and wines and forget about the rest). In science, things are classified based on the type of thing they are according to their essential features. Different kinds may be grouped or classed together.
Scientific classification is most often based on what the things ARE (not their function, cause, etc.), so scientific classification depends on scientific definition.

It depends on scientific definition because things are classified based on what they ARE, based on their essential and defining features.

Because they are defined by their diagnostic criteria or symptoms that may or may not be present in each case.

For clinicians who need to make a diagnosis. BUT must understand that those criteria are NOT essential defining features and should not be used to construct a scientific system of classification.

Polythetic mental disorders may help with diagnosis (as they contain symptoms that may/may not be present) but they CANNOT be extrapolated to a scientific system or research as they do not have essential defining features.

identifying the signs and symptoms of the disorder (which are NOT essential defining features).
The DSM-5 must be clear about the difference between a symptom and a definition.

… symptom and a definition.

The DSM-5 wrongly states that disorders are:

a. the diagnostic criteria (signs/symptoms).
b. the behavioural effects of the disorder.
c. the behavioural effects of the sign/symptoms.
d. the phenomenology of the disorder (how it feels to have that disorder).
e. the causes of the disorder.
f. the examples/particular cases of the disorder.
g. the individual as the bearer of the disorder.

How it feels to have that disorder.

they are polythetic, they may or MAY NOT be present.

The DSM-5 assumes that:

a. clinical diagnosis;

b. operational definitions;

c. classifications;

are defining features of a mental disorder.

E.g., a clinical diagnosis is not the scientific definition of a disorder. But a clinical diagnosis is dependant on a separate scientific definition of a mental illness.

How can the ‘individual disorder definitions’ be used for both clinical and research purposes?
It would be fine for just clinical purposes but to say the document is both a diagnostic and scientific document is a contradiction.

‘Categorical systems do not capture scientific observations’? This is the justification for using polythetic diagnostic criteria. Those systems are absolutely appropriate for clinical treatment but not for constructing scientific definitions.
They have conflated the clinical task with the scientific task.

While there is a push to use dimensional approaches to diagnosis (because a lot of symptoms or diagnostic criteria appear in many different disorders) this might just indicate that the diagnostic criteria are not being used illegitametely, and are not actually measuring what they are supposed to measure so the symptoms are popping up across the board.

These confusions might not affect diagnosing clinicians but they might affect research… and the problems will get perpetuated and added to. When dimensionality is introduced, the problems in the DSM-5 will expand, like compound interest.

('if they change to dimensional, it will be even more of a dog's breakfast' - Fiona)

Diagnosing someone based on their symptoms across different disorders may not be so bad for a clinician but for a researcher the problems will get more confusing, added to more and will expand. It will be like compounding interest in the DSM-6.