Mood disorders like depression or bipolar disorder are defined by traits and symptoms that tend to ebb and flow, personality disorders are more of a constant state than a temporary trait.

While a person experiencing depression or anxiety can recognize their symptoms and differentiate between their "normal" self and their depressed/anxious self, a person with a personality disorder only knows life through the lens of that disorder.

• The disorder falls under an umbrella known as "Cluster B" personality disorders, which also include antisocial personality disorder and narcissistic personality disorder.
• On the whole, Cluster B personality disorders are characterized by "intense, unstable emotions, distorted self-images, and difficulty in relationships."
• Whereas the better-understood Cluster B disorders have a clear, disruptive impact on people's lives, it's been harder for psychologists to agree if and how HPD uniquely disrupts people diagnosed with the disorder.