The DSM-IV-TR (2000) defines a personality disorder as:
“An enduring pattern of inner experience and behavior that deviates markedly from the expectations the individuals culture (and is manifested in two or more of his or her areas of mental life:) cognition, affectivity, interpersonal functioning, or impulse control.”
Such a pattern is rigid, long-term (stable), and recurrent. It manifests itself in all areas of life (it is pervasive). It is not owing to substance-abuse or a medical condition (such as head trauma). It renders the subject dysfunctional “in social , occupational, or other important areas” and this impairment causes distress.
In the DSM, there are 10 distinct personality disorders (Paranoid, Schizoid, Schizotypal, Antisocial, Borderline, Histrionic, Narcissistic, Avoidant, Dependent, Obsessive-compulsive) and one catchall category, Personality Disorders NOS (Not Otherwise Specified).
Personality disorders with marked similarities are grouped into clusters.
Cluster A (the Odd or Eccentric Cluster) includes the Paranoid, Schizoid, and Schizotypal Personality Disorders.
Cluster B (the Dramatic,...