The New DSM-5: Personality Disorders
In this article, we discuss the category of disorders called personality disorders (PDs). The first important change is that PDs are no longer diagnosed on a separate axis. As we discussed in our first article, DSM-5 has eliminated the multi-axial system. Personality disorders were originally targeted for sweeping changes that ultimately did not get passed. The DSM-5 work group had proposed a dimensional approach to PD diagnosis in lieu of the current categorical method. This rapidly became one of the most hotly contested topics during the DSM-5 revision process. We'll review the categorical and dimensional models as both are included in the new DSM-5, but in different sections.
Diagnostic differences: Personality disorders compared to other psychiatric disorders
Most psychiatric disorders are evidenced by a complete and total deviation from normal and healthy functioning. Clearly, Major Depression, Schizophrenia, and PTSD are not found in the vast majority of people. Either you have these disorders, or you do not. You can't have a wee bit of Schizophrenia. You might liken this to an ordinary light switch: either it's on, or it's off. However, unlike schizophrenia, everyone has a personality and you can indeed have a wee bit of nearly any personality trait. In this respect, personality represents a continuum, ranging from healthy to disordered. This is similar to a dimmer light switch. There are many points along the way from off to on.
From a diagnostic perspective, conditions that fall into discreet categories (such as Major Depression, Schizophrenia, PTSD, or pregnancy for that matter) are well-suited for a categorical method of diagnosis. In this method, you assess and tally symptoms to determine if they meet the diagnostic criteria for a particular category of disorder. We are all familiar with this method because the DSM relies upon a categorical method of diagnosis. However, conditions that represent a continuum, such as personality, are better suited to a different diagnostic approach called a dimensional model. Recognizing these important distinctions, the DSM-5 PD work group developed a dimensional diagnostic model for PDs.
DSM-5 personality disorders: What has changed?
In a nutshell, nothing has changed. Despite the efforts of the DSM-5 PD workgroup, the ten "official" PD diagnoses remain unchanged from DSM-IV. So, what's all the fuss about then? Clinicians can now choose to use the dimensional model developed by the DSM-5 workgroup. As mentioned, the DSM-5 work group developed this model to replace the existing categorical method due to its numerous and significant problems. However, their proposal received so much criticism that the Board of Directors ultimately rejected it. Instead, it was relegated to Section III: Emerging Measures and Models (some people jokingly refer to this section as the Siberia of DSM). The model developed by the work group is now called the Alternative DSM-5 Model for Personality Disorders. Despite its diminished status in Section III, this alternative model is expected to become the "official" diagnostic approach for PDs at some point in the future. Therefore, clinicians may wish to familiarize themselves with it.
Practical and scientific problems plague personality disorder diagnosis
Our current categorical diagnostic approach is ill-suited for PDs because personality is a continuous, multi-faceted dimension. For example, let's consider grandiosity, a characteristic trait of Narcissistic PD. Where is the line of demarcation between health and disorder on the continuum from healthy self-esteem, to selfishness, to self-centered entitlement? How do we decide this? Are there differences across cultures and genders that should be taken into account? Trying to use a categorical approach with a continuous dimension like grandiosity is similar to trying to fit a square peg in a round hole. The numerous problems with our current categorical method of diagnosis are evidence of this poor fit.
Andrew Skodol, M.D. was the chair of the DSM-5 PD work group. He discussed these problems at the American Psychiatric Association Annual Meeting on May 18th, 2013. Topping the list of problems are the lack of empirical support and the non-specificity of diagnostic criteria, making accurate diagnosis very difficult. Indeed, clinicians often avoid making a PD diagnosis, using "Diagnosis Deferred" or "Personality Disorder NOS." In fact, PDNOS is the most frequently diagnosed Personality Disorder! Other significant problems included extensive co-occurrence with other personality disorders and with other categories of disorders; extreme heterogeneity; arbitrary diagnostic thresholds, and limited clinical utility. The proposed dimensional model, described below, aspires to eliminate many of these difficulties.
The Alternative DSM-5 Model for Personality Disorders
Located in Section III, Emerging Measures and Models, is the alternative DSM-5 model for diagnosing PDs. It is expected that some version of this model will eventually replace the current categorical model. There are two primary criteria (along with the usual requirement of stability across time, person, and place):
1) Personality functioning
a. Impairment in personality functioning is rated along a continuum. Moderate or greater impairment is required for diagnosis of PD
i. 0 = little to no impairment
ii. 1 = some impairment
iii. 2 = moderate impairment
iv. 3 = severe impairment
v. 4 = extreme impairment
b. Four elements of personality functioning are identified with descriptive charts to evaluate degree of impairment:
2) Pathological personality traits (one or more)
a. Derived from the well documented 5-factor Model of Personality (FFM) and Personality Psychopathology Five (PSY-5).
b. Below are the five broad trait domains containing 25 specific personality trait facets. They can be assessed with several psychometric tests.
i. Negative affectivity (vs. emotional stability)
ii. Detachment (vs. extraversion)
iii. Antagonism (vs. agreeableness)
iv. Disinhibition (vs. conscientiousness)
v. Psychoticism (vs. lucidity)
In the alternative model, only six specific personality disorders are listed, compared to the current ten. These are antisocial, avoidant, borderline, narcissistic, obsessive-compulsive, and schizotypal. The remaining four did not make the cut due to lack of research evidence to support inclusion (schizoid, paranoid, histrionic, dependent). However, with this new dimensional method, it is now possible to diagnose a personality disorder based on traits (Personality Disorder- Trait Specified). Another useful feature of this model is that it can be used to assess personality functioning and traits, regardless of whether or not a personality disorder is suspected. This increases the clinical utility of the model because it helps clinicians to identify areas of relative strengths. Recent research indicates it is beneficial to identify resiliency as this information facilitates the selection of appropriate therapeutic interventions and strategies.