Objective: The largest clinical epidemiological surveys of personality disorders have been based on unstructured clinical evaluations. However, several recent studies have questioned the accuracy and thoroughness of clinical diagnostic interviews; consequently, clinical epidemiological studies, like community-based studies, should be based on standardized evaluations. The Rhode Island Methods to Improve Diagnostic Assessment and Services project is one of the largest clinical epidemiological studies to use semistructured interviews to assess a wide range of psychiatric disorders conducted in general clinical outpatient practice. In the present report, the authors examined the frequency of DSM-IV personality disorders in a patient group and the comorbidity among them.
Method: Eight hundred fifty-nine psychiatric outpatients were interviewed with the Structured Interview for DSM-IV Personality upon presentation for treatment.
Results: Slightly less than one-third of the patients were diagnosed with one of the 10 official DSM-IV personality disorders (N=270, 31.4%). When the patients with personality disorder not otherwise specified were included, the rate of any personality disorder increased to almost half of the group (N=391, 45.5%). The majority of patients meeting criteria for one of the specific personality disorders were diagnosed with more than one. Avoidant, borderline, and obsessive-compulsive personality disorder were the most frequent specific diagnoses.
Conclusions: Personality disorders, as a group, are among the most frequent disorders treated by psychiatrists. They should be evaluated in all psychiatric patients because their presence can influence the course and treatment of the axis I disorder that patients typically identify as their chief complaint.