646 Personality Disorders
or 2) the individual’s personality pattern m eets the general criteria  for a personality dis-
order, but the individual is considered to have a personality disorder that is not in-
cluded in the DSM-5 classification (e.g., passive-aggressive personality disorder).
The personality disorders are grouped into thre e clusters based on descriptive similarities.
Cluster A includes paranoid, schizoid, and schi zotypal personality diso rders. Individuals with
these disorders often appear odd or eccentric. Cluster B includes antisocial, borderline, histri-
onic, and narcissistic personality disorders. In dividuals with these disorders often appear dra-
matic, emotional, or erratic. Cluster C in cludes avoidant, dependent, and obsessive-
compulsive personality disorders. Individuals with these disorders often appear anxious or
fearful. It should be noted that this clustering system, although useful in some research and ed-
ucational situations, has serious limitations and has not been consistently validated. 
Moreover, individuals freque ntly present with co-occu rring personality disorders
from different clusters. Prevalence estimates fo r the different clusters suggest 5.7% for dis-
orders in Cluster A, 1.5% for disorders in Cl uster B, 6.0% for disorders in Cluster C, and
9.1% for any personality disorder, indicating frequent co-occurrence of disorders from dif-
ferent clusters. Data from the 2001–2002 National Epidemiologic Survey on Alcohol and
Related Conditions suggest that  approximately 15% of U.S. adults have at least one per-
sonality disorder.
Dimensional Models for Personality Disorders
The diagnostic approach used in this manual  represents the categorical perspective that
personality disorders are qualit atively distinct clinical synd romes. An alternative to the