The problems with diagnosing dysfunctional behaviour (and a great audio podcast on abnormality)

Here is an absolutely brilliant audio podcast from Todd Daniels, entitled "What is Normal?" He's a psychologist from the US, and he's got 50 audio podcasts on a range of issues. He explains things with plenty of examples, and I think it's definitely worth checking out. It's a little lengthy though, so here are some of the main issues:

Dysfunctional behaviour is a tricky term to define. Here's a working definition generally used by the psychology community:

It is behaviour which is deviant, maladaptive, and personally distressing. 

It fits pretty well with Rosenhan and Seligman's definition, too. Statistical infrequency, deviation from ideal mental health and deviation from social norms all links to the characteristic of "deviant", and failure to function adequately comes under both "maladaptive" and "personally distressing".

So, it seems like a great definition. But, there are limitations.

Not all behaviours considered dysfunctional have all three characteristics - so can they be defined as dysfunctional or abnormal? Sometimes. Smoking is an addiction, but unlike most addictions, it's not really considered dysfunctional, even though it's maladaptive and most find it personally distressing. On the other hand, depression is considered dysfunctional, even though it's likely more people suffer from depression than get addicted to cigarettes.

So, a major problem with diagnosing dysfunctional behaviour is not only defining it, but knowing how many characteristics of the definition behaviour has to exhibit to be labelled as dysfunctional.

Another problem is subjectivity, which leads to both poor validity and poor reliability. Whilst the DSM attempts to standardise diagnoses, the person who's diagnosing the disorder has room for subjectivity. For example, the DSM criteria for a phobia states that in order to be diagnosed, the fear of the object or situation must be "excessive". But, what's excessive? It changes according to the person. If the psychologist also fears the object, they might think there's a higher threshold for excessive than somebody who doesn't understand or share the same fear. So, a lot of diagnoses are actually based on bias of other people. Definitions also suffer from this weakness, as seen in the "observer discomfort" criterion for failure to function inadequately. Thus, there is unlikely to be uniformity in diagnoses, which leads to poor internal validity due to the confounding variable of bias, as well as poor reliability due to the individual differences of clinicians. 

Ethnocentrism is also an issue, related to this. Depending on our own culture, we may or may not perceive a behaviour to be abnormal. For example, if a man were to wear clothes such as dresses, or skirts, this in many Western cultures could be labelled as both deviant, and causing observer discomfort. It's statistically infrequent, and deviates from social norms. However, in Scotland for example, men wear kilts, which are essentially skirts. And, in the LGBT community, it wouldn't be considered abnormal. So, there's a fair amount of ethnocentrism within diagnoses. It's a fairly similar point to subjectivity, but you can extend it to points such as the fact that diagnoses cannot be generalised externally due to lacking population validity in other communities. They're also likely to lack temporal validity, due to the changing nature of cultures. Furthermore, it's arguable that the concept of dysfunctional behaviour lacks construct validity, as it's difficult to define. And thus, is it really nomothetic? 

Essentially, diagnosing dysfunctional behaviour is complex and often inaccurate.