Categorical clarifications have the advantage of clarity. No shades of gray; it’s either black or white. Of course,  this is a quite efficient approach when things are strictly black and white. No ambiguity, no confusion. But these very advantages become weaknesses when the reality actually presents the observer with shades of gray. As there is no in-between, the nuances will be stripped of their defining characteristics and rigidly forced in one of the existing categories.

Such approach remains simple but it is also simplistic in the worst sense. Reality is butchered with gray turned into white or black depending on observer preference or bias. Furthermore, there is a risk that the gray will simply be missed by someone whose conceptual foundation, when it comes to colors, includes only black and white. It’s been shown that our perception of realty is concept based, i.e. no concepts equals no perception. When this is the case the gray will no longer be misclassified (that’s the positive) as black or white as it will no longer be perceived at all (a negative that I believe outweighs the positive with several orders of magnitude).

Case and point: my residents see Cluster A or B or C personality disorders. The better ones even see traits. But not even the best see in-between. When someone does not conform to the DSM typology they could get a “the patient does not have any Cluster A or B or C personality traits” formulation of sorts. In other words, there is black, and there is white, but there is no gray.

My suggestion: think (and look) for dimensions instead of categories. We all have personality dimensions (tones of grey).

The model I use is Costa and McCrae’s Five-Factor Model where the dimensions are:

O – Openness to experience (novelty seeking) versus Closeness

C – Conscientiousness versus Laissez-faire

EExtraversion versus Introversion

AAgreeableness versus Dis…

N – Neuroticism versus Emotional Stability

There are a few advantages of using a dimensional trait (rather than categorical) approach:

1. The factors are based on laborious statistics (factor analysis) and not opinion based constructs.

2. There is evidence about the factors genetic (albeit complex) genetic transmission. Which also helps to nicely bridge traditionally separated domains of assessment/inquiry such as Axis 1 (biological in origin, i.e. amendable through drug treatment) versus Axis 2 (psychological in origin, therefore amendable through psychotherapy).

3. The factors are measurable by testing (also public domain, free of charge online testing is available at a click of a button).

4. The factors have been shown to be universal, culturally independent construct (i.e. can be measured in China as they can be measured in Germany) (McCrae & Costa, 1997).

5. Understanding the dimensions is useful for insight and improvement through therapy (and these personality “observations’ can be shared with the patient right away) (Costa & McCrae, 1992).

6. The factors are stable over decades (average 45 years) (Soldz & Vaillant, 1999).

But even without former testing, keeping the traits in mind while sitting down with your patient, is a more straightforward model that you can use to learn about important aspects of their persona. Rather than basing your learning about the patient on complicated (and only partially proven) models about how the persona and the mind work, it’s just so much more straightforward and easier to have a trait-informed assessment.


Costa, P. T., Jr., & McCrae, R. R. (1992). Normal personality assessment in clinical practice: The NEO Personality Inventory. Psychological Assessment, 4, 5-13.

McCrae, R. R., & Costa, P. T., Jr. (1997). Personality trait structure as a human universal. American Psychologist, 52, 509-516.

Soldz, S., & Vaillant, G. E. (1999). The Big Five personality traits and the life course: A 45-year longitudinal study. Journal of Research in Personality, 33, 208-232.