Personality disorders: Diagnostic issues
Differentiating personality disorders from other psychiatric disorders
An individual with a personality disorder has a deep-seated maladaptive style as part of their personality. The maladaptive personality style must be pervasive and long-standing from the teenage years onward.
If, according to the history from the patient or the family, the onset of the personality difficulties is recent, the clinician must consider a psychiatric diagnosis other than a personality disorder.
Disorders that may have similar features as personality disorders include:
- major depressive disorder
- generalized anxiety disorder
- panic disorder
- posttraumatic stress disorder
Sometimes, these conditions bring out the worst in a person's personality, making it seem that they have a personality disorder. They may appear to have a personality disorder as they become more demanding, inappropriately persistent, emotionally reactive and irritable.
It is important to clarify whether those patients who appear to have a personality disorder do in fact have the disorder, or whether they are experiencing, for example, a refractory depression that is bringing out the worst in their premorbid personality. Our clinical assessments tend to be cross-sectional, whereas personality disorders require a longitudinal review of functioning.
Recent onset, rather than long-standing personality difficulties, suggest that these characteristics may reflect a psychiatric disorder other than personality disorder.
Some patients may seem to have a personality disorder when they are dealing with characteristic stressors that are difficult for them. However, when the history taken from the patient or the people in the patient's support system indicates that the maladaptive behaviours are limited to a response to the difficult stressors, then it is not a personality disorder.
It is important to have collateral history from family members or significant others about the chronicity of the behaviours. As well, patients can themselves describe what they were like before they developed the other psychiatric disorder (e.g., depression, hypomania, generalized anxiety state). When patients have a remission from this other psychiatric disorder, they no longer appear to have a personality disorder.
In the case of depression, ask the patient to describe their personality prior to the depression. Get a collateral history from family members or significant others who can confirm whether the maladaptive behaviours occur exclusively in the context of a psychiatric condition other than personality disorder, or whether they are long-standing from childhood. Keep in mind that no matter how characterological the presentation, the diagnosis is unlikely to be a personality disorder if there is no supportive evidence from earlier in life.
It is best to defer a personality assessment until the acute psychiatric disorder has been successfully treated.
Borderline personality disorder: recognition and management (NICE guideline CG78, 2009)
Antisocial personality disorder: prevention and management (NICE guideline CG77], 2008)
Clinical Practice Guideline for the Management of Borderline Personality Disorder (National Health and Medical Research Council, 2012)
Treatment guidelines for personality disorders (Project Air, 2015)