As defined by the fourth edition of the Diagnostic and Statistical Manual of the Mental Disorders (DSM-IV; American Psychiatric Association, 1994), a personality disorder is “an enduring pattern of inner ex- perience and behavior that deviates markedly from the expectations of the individual’s culture, is pervasive and inflexible, has an onset in adolescence or early adulthood, is stable over time, and leads to distress or impairment” (p. 633). The pattern is manifested in two (or more) of the following areas: (1) cognition (i.e., ways of perceiving and interpreting self, other people, and events), (2) affectivity (i.e., the range, intensity, lability, and appropriateness of emotional response), (3) interpersonal functioning, and (4) impulse control.

Given this definition, clinicians should keep two critical questions in mind when determining whether a personality disorder diagnosis is warranted:

1. Do the relevant inner experiences and behaviors represent inflexible, pervasive, and long-standing patterns and not just tran- sient or episodic effects related to a patient’s current psychiatric state?

2. Do these long-standing patterns create significant distress or significantly impair functioning across multiple domains (e.g., so- cial and occupational)?

Such judgments are ultimately left to the clinician as no distinct cutting points have been proposed or identified empirically to establish the boundaries between pathological and normal personality, between personality disorders and Axis I disorders, or between the various personality disorders themselves (Zimmerman, 1994).