Where’s the Person in Personality Disorders?

People with personality disorders (PDs) have, by definition, a set of traits or enduring dispositions that aren’t working for them. Everyone has a “personality,” and everyone has certain traits. In personality disorders, these traits get in the way of an individual’s ability to adapt to life’s changing circumstances.

When diagnosing PDs, mental health professionals in the United States now have little choice but to decide what category best fits an individual’s symptoms. However, the Alternative Model of Personality Disorders (AMPD) plus the International Classification of Diseases-11 (ICD-11) provide a way out of this all-or-nothing dilemma. Instead of putting people into diagnostic bins, they can use dials to rate people along all of the AMPD dimensions.

Still needed, though, is a way to account for the challenges people with PDs experience when they make their way through life. This is where an individual is assessed for having disturbances in identity (sense of self) or in relations to others. The question is, how much do these separate domains help in both (a) diagnosis and, more importantly, (b) treatment? After all, what matters to people with PDs is how they can get better.

Taking Apart the Pieces of Personality Disorders

According to Aarhus University’s Lennart Kiel and colleagues (2025), there’s reason to wonder whether identity disturbance specifically is needed above and beyond pathological personality traits in understanding the PDs. Where does personality leave off, in other words, and the person begin?

You might think that this is an esoteric argument reserved for academicians to debate. But there are important practical implications. Maybe you’re a bit high on negative affectivity, one of the traits included in the AMPD. So you worry a lot and tend to become sad. How much, though, is this part of the very way in which you see yourself? The AMPD traits don’t specify where you, the “person,” lie in this constellation of features.

In general, personality trait models take very little heed of the “person” in whom these traits combine. The Five Factor Model (FFM) traits (openness to experience, neuroticism, extraversion, conscientiousness, and agreeableness) are the most frequently used to define personality in the trait model. However, nowhere in this model does it ask you to indicate how conscientious you “feel” you are, or whether you see yourself as agreeable.

How Much Does the Person Matter?

Comparing a community sample of 776 participants (average age 41 years) and a clinical sample of 77 (average age 30 years), the Danish author team administered FFM trait measures, AMPD measures, scales measuring degree of daily-life impairment, and disturbances in identity.

The three parts to the identity measure were unconsolidated identity (“I know who I am”), disturbed identity (“The things that are most important to me change pretty often”), and lack of identity (“I feel empty inside”).

The findings showed that identity disturbance indeed played a role independent from, or even greater than, personality traits in predicting functional impairment. When scores on identity disturbance were controlled for statistically, AMPD traits showed little ability to predict adaptational problems in daily life.

It makes sense that identity disturbance would have such a vital role in predicting the trouble people might have in navigating life’s challenges. Lacking a central core of the self means that you can’t fall back on a sense of continuity over time. You know “who” you are because you are aware of where you’ve been and where you’re going in life. Without that, your experiences will lack meaning and cohesion. This might be what is truly at stake in personality disorders.

Personality Disorders Essential Reads

Why We Still Need Categories in Personality Diagnosis

Why Some People Never Seem to Grow Up

Bring Back the Person, Please

In diagnosing a psychological disorder, there is always a risk that the person gets left out of the picture. Unlike a medical diagnosis, a PD diagnosis uses the very essence of a person as part of its set of criteria. It doesn’t matter what your personality is like to have a healthcare professional diagnose you with the flu. But it does if you’re being evaluated for a psychological diagnosis and particularly one that takes personality—that essence of your traits—into account.

Humanistic approaches in psychology indeed regard disturbances in one's sense of self as fundamental both to diagnosis and treatment. You can take a medication for the flu (maybe, or at least be advised to rest), but with a PD, the treatment must be adapted to the features that make you unique. These include your life history, your strengths and weaknesses, your relationships, and all the many facets that contribute to your unique qualities.

Although the purpose of the Kiel et al. study was to address a somewhat technical issue within the field, its main message carries far beyond this narrow intent. By showing that how you define yourself can influence how well you can adapt to life, the study transcends methodology.

To sum up, if you’re trying to figure out how to make your way through life, knowing that your sense of identity plays such an important role can become a focus of your own journal of self-discovery.