We diagnose personality pathology by grouping pathological personality traits into categories. The DSM approach to personality disorders is the official diagnostic system of the mental health field. The DSM system defines a personality disorder as “an enduring pattern of inner experience 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.” DSM-IV-TR lists ten personality disorders grouped into Clusters A, B, and C. The eleventh diagnosis, Personality Disorder Not Otherwise Specified, is intended as a catch basin diagnosis for people who do not fit the other ten diagnoses.

Two additional personality diagnoses, depressive and passive-aggressive (negativis-tic), are listed in the appendix as awaiting further study. Cluster A disorders, which include paranoid, schizoid, and schizotypal personality disorders, are characterized by odd or eccentric traits. Cluster B disorders, including histrionic, borderline, narcissistic, and antisocial personality disorders, are seen as impulsive and emotionally erratic. Cluster C disorders include avoidant, dependent, and obsessive-compulsive personality disorders and are associated with high anxiety.