Personality Disorder: Understanding Dimensionality

The story so far: The DSM-5, due out in 2013, will be the same old book in new covers. The exception is personality disorders, which gets a major overhaul. Not coincidentally, this is the one realm of mental illness where big pharma is conspicuously absent.

My last two blog pieces - Decisions, Decisions, and Bringing Order - looked at the changes on the “categorical” side of personality disorders. Five out of ten of the present disorders will get the boot, while the five left standing (antisocial/psychopathy, avoidant, borderline, obsessive-compulsive, and schizotypy) receive further clarification. The weakness with categories is inevitable overlap, but rather then pretending this doesn’t exist, the DSM-5 openly adopts interchangeable parts, with six “trait domains” (negative emotionality, introversion, antagonism, disinhibition, compulsivity, and schizotypy) further subdivided into “facets.”

Thus, the new borderline “type” (which replaces the term “disorder”) is loaded with six negative emotionality trait domains and two antagonism domains, while the new antisocial/psychopathy type is heavy on antagonism (six in all) and light on negative emotionality (zero, in fact). The two borderline antagonism facets (hostility and aggression) reappear word-for-word in antipsychocial/psychotic.

Kind of like IKEA. The parts may be the same, but each piece of furniture - one hopes - is very different. So what would happen if we were to dispose of the concept of furniture altogether? Funny you asked.

Enter the “dimensional” model. The same bits and pieces are there - namely the general trait domains of negative emotionality, introversion, antagonism, disinhibition, compulsivity, and schizotypy, plus the more specific facets - but instead of looking for labels, we are looking for shadings. Instead of asking “Which one?” (as in borderline or antisocial) we are asking “How many?” and “How much?”

The DSM-5 trait domains are derivative of, and roughly correspond to, the traits in the five-factor model (FFM), already in wide use in clinical practice. The FFM tests for “openness to experience”, “conscientiousness”, “extraversion”, “agreeableness”, and “neuroticism” (OCEAN).

A quick scan, however, reveals that the FFM and DSM-5 investigate essentially the same phenomenon from entirely different viewpoints (“extraversion” vs “introversion”, “agreeableness” vs “antagonism”, “conscientiousness” vs “disinhibition” and “compulsivity”). Whereas the FFM looks at our potential, the DSM looks at what is holding us back.

A good illustration of this is the FFM’s “openness to experience” trait, which has no apparent correspondence in the DSM-5. The opposite to openness to experience is stuck in the mud, which you can hardly associate with any kind of mental disorder. In this context, stuck in the mud is simply less desirable than being creative and intellectually adventurous.

Now let’s examine the one DSM-5 trait with no seeming FFM counterpart. “Schizotypy” broadly describes strange thinking and behavior. Its opposite? May I suggest stuck in the mud? In other words, in a DSM setting, stuck in the mud comes across as a desirable trait. Certainly, no one calls 911 to complain about their boring wife or husband.

The DSM-5 calls for clinicians to rate all 37 facets which make up the six domains on a four-point scale, which invites the instant criticism of clinical unwieldiness. According to Allen Frances, who chaired the DSM-IV, blogging on Psychology Today:

Unfortunately, the reach of DSM-5 far, far exceeds its grasp. Only by going to the website yourself and reviewing the DSM-5 dimensional suggestions can you get a feel for just how remarkably ad hoc, idiosyncratic, and cumbersome they are. I have discussed the suggestions for dimensional personality disorder ratings with a number of experts (and this is also my area) and none of us could decipher the proposal, much less conceive of its ever being workable. One described it as an example of "too many research cooks spoiling a clinical broth".

Dr Frances’ criticism may well be valid, but it also can be interpreted as an egregious case of DSM-worthy “lazy clinician syndrome.” We see this every day in doctors who profess to be far too busy to monitor their patients for weight and blood sugar levels and other red flags when prescribing meds with notoriously high metabolic risks, not to mention other high crimes and misdemeanors.

Personality is fiendishly time-consuming and complex. Clinicians want it quick and simple. But what about our interests?

Much more to come ...

Previous Pieces

Taking It Personally: The DSM-5 and the Narcissism Controversy

Let's Play Spot the Personality Disorder 

Why is Spotting the Personality Disorder So Damned Hard? 

Personality Disorders: Decisions, Decisions ...

Bringing Order to Personality Disorder