The relationship between generalized social phobia and avoidant personality disorder in a national mental health survey.

Objective: There has been ongoing clinical controversy dating back to the revised third edition of the Diagnostic and Statistical Manual of Mental Disorders concerning the boundaries and extent of overlap between Axis I generalized social phobia (GSP) and Axis II avoidant personality disorder (APD). This study sought to examine the relationship between the fourth edition of Diagnostic and Statistical Manual of Mental Disorders GSP and APD in a large nationally representative sample of the United States population.
Method: We used the National Epidemiologic Survey on Alcohol and Related Conditions (n=43,093; age 18+; response rate=81%) to study fourth edition of Diagnostic and Statistical Manual of Mental Disorders Axes I and II psychiatric disorders, assessed by a reliable semi-structured in-person interview.
Results: The lifetime prevalence was 2.8% for GSP and 2.4% for APD. The overlap between GSP and APD varied according to the number of GSP social situations feared. Although 36.4% of individuals with GSP were diagnosed with APD, the majority (57.3%) of individuals with GSP who feared all 13 social situations assessed were diagnosed with APD. Nearly 40% of individuals with APD also had GSP. Compared to individuals with GSP alone, individuals with comorbid GSP and APD showed significantly lower mental health-related quality of life on the Medical Outcomes Study Short Form, more interaction and observation fears, and an increased likelihood of having other psychiatric disorders such as major depression.
Conclusions: APD and GSP show a high degree of overlap (16-57%), depending on the number of social situations feared. Overall, results suggest that APD and GSP appear to be highly related, but potentially separable constructs. Further research is needed to identify the determinants and consequences of having either or both diagnoses.