Personality Disorder Diagnoses not all that stable over time.

Mark Dombeck, Ph.D. was Director of Mental Help Net from 1999 to 2011. Dr. Dombeck received his Ph.D. in Clinical Psychology in 1995 ...Read More

Personality Disorder Diagnoses are not all that stable over time.

The Diagnostic and Statistical Manual of Mental Disorders (DSM – the manual used by doctors to diagnose mental disorders) differentiates between disorders like depression that are supposed to be superimposed upon essentially healthy people, and personality disorders, which are assumed to be present from a young age, and therefore a permanent feature of those people’s basic disordered state. This is to say that the DSM assumes that an essentially healthy person might get depressed, and then recover to be as healthy as they were before. This is not the case for a personality disordered person, because they are assumed to be permanently unhealthy; their state of unhealth is woven into their being rather than being superimposed on top of a healthy self. Disorders of the first sort are known as “Axis I” disorders, while disorders of the second sort are known as “Axis II” disorders.

Though no doubt well intentioned when it was put in place, this division between Axis I and Axis II appears to be turning out to be not so cut and dried. Recent research, such as the paper “Ten-Year Stability of Personality Disorders Among Outpatients With Mood Disorders” published in the Journal of Abnormal Psychology by Drs. Emily Durbin and Daniel Klein (February, 2006, Vol. 115, No. 1, 75-84), now suggest that personality disorders are not all that stable over time, but rather tend to change as people age and mature (and get treatment).

This study followed 142 people diagnosed with depression in one form or another over 10 years, stopping every 2.5 years to do follow-up measurements. Over 100 people completed all five measurements made over the 10 year period. Participants were interviewed and tested to establish personality disorder diagnoses and normal personality trait measurements.

The study found that:

• The stability of personality disorder diagnoses was poor over the course of 10 years – meaning that repeated measurement at 2.5 year intervals failed more often than not to establish the same personality diagnoses in the same people.
• Measures of personality disorder traits (not diagnoses but tenancies) were moderately stable over 10 years, but not as stable as were measures of normal personality traits
• Cluster B personality disorders (antisocial, borderline, histrionic, narcissistic) were more stable in their diagnoses and tendencies over the 10 year period than were either cluster A (paranoid, schizoid, schizotypal), or cluster C (avoidant, dependent, obsessive-compulsive).

There were other findings too, but they were more detailed in nature, and I decline to describe them in the interests of simplicity. The take home message here is that personality disorders do change over time although they do so only moderately, and some of them more than others. When you consider that many of the Axis I disorders are chronic in nature themselves (e.g., recurrent depression, bipolar disorder, etc.), the rational for continuing to maintain the distinction between Axis I and Axis II classifications starts to erode a bit. This might take another 10 or 20 years to occur (these things move slowly), but I’m guessing that we’ll see some evolution of the diagnostic system in the future to better accommodate this sort of finding.