The Dimensions of Personality

By John M Oldham, MD

Last year, I was asked to post a short video for “Vumedi Week 2025,” an annual collection of brief medical educational videos. I provided a link to that video in my August, 2025 blog, entitled “Borderline Personality Disorder, Revisited.” Recently, I was asked to participate in Vumedi Week 2026, this time to post a video entitled “Personality Disorders: Transitioning to a Dimensional DSM-5 Model and Proposed DSM-6 Single-PD Framework.” Here is the link to that video: https://www.vumedi.com/video/personality-disorders-transitioning-to-a-dimensional-dsm-5-alternative-model-and-proposed-dsm-6-sing/InBlcnNvbmFsaXR5LWRpc29yZGVycy10cmFuc2l0aW9uaW5nLXRvLWEtZGltZW5zaW9uYWwtZHNtLTUtYWx0ZXJuYXRpdmUtbW9kZWwtYW5kLXByb3Bvc2VkLWRzbS02LXNpbmci:1wz0Ef:B6RNcupgOEg-mLuupVrWVdl57uR5JsXCYqkhBSbFmuA/.

In this posting, I briefly describe the evolution of our classification system of the personality disorders. For decades, this has followed a “categorical” medical model—reflecting traditional definitions of mental illnesses as discrete entities with “construct validity,” such as bipolar disorder, major depressive disorder, and many others. Categorical conditions are considered to be demonstrably unique, such as being male or being female. In contrast, a dimensional approach describes something on a continuous scale, from least to most, such as height or weight. And for many years, scholars have argued that personality is better conceptualized dimensionally. Each of us has a unique combination of personality traits, some of which are more prominent than others. Like blood pressure, too much, or maybe too little, of a given trait could become a problem. That’s the principle behind the Personality Styles/Personality Disorders Continuum on this NPSP25 website.

The American Psychiatric Association took a step in the dimensional direction in the 5^th edition of its diagnostic manual, DSM-5, by including the “Alternative DSM-5 Model for Personality Disorders” in the section on “Emerging Measures and Models.” In the video, I summarize that model, and then I review the progress of a current workgroup that is developing recommendations for the next edition of the diagnostic manual. If you’re interested, take a look!