Background: To investigate whether each of three DSM-III-R phobic disorders (simple phobia, social phobia, and agoraphobia with panic attacks) is familial and "breeds true."
Design: Rates of each phobic disorder were contrasted in first-degree relatives of four proband groups: simple phobia, social phobia, agoraphobia with panic attacks, and not ill controls. Phobia probands were patients who had one of the phobia diagnoses but no other lifetime anxiety comorbidity.
Results: We found moderate (two- to fourfold increased risk) but specific familial aggregation of each of the three DSM-III-R phobic disorders.
Conclusions: These results support a specific familial contribution to each of the three phobia types. However, conclusions are limited to cases occurring without lifetime anxiety comorbidity and do not imply homogeneity within categories.