What defines a personality disorder?

A personality disorder is predominantly characterized by enduring patterns of thinking, behaving, and relating to others that are significantly different from cultural expectations. These patterns are stable over time and can cause substantial distress or impairment in social, occupational, or other important areas of functioning. Individuals with personality disorders often exhibit rigid traits and maladaptive behaviors that can affect their relationships and interactions with others.

In contrast, the other options do not accurately encapsulate the permanence and the pervasive nature of personality disorders. For instance, a temporary pattern of behavior suggests a lack of stability, which is not the case for personality disorders that are deeply ingrained. Similarly, a phase of psychological development implies a transitory state, rather than a chronic state of being. Lastly, a reaction to situational stress would imply a response to external circumstances rather than an internalized way of interacting with the world, which is a hallmark of personality disorders. Such distinctions clarify why the definition focusing on enduring patterns is the most accurate.