Although family studies could challenge categorical distinctions between agoraphobia and panic disorder, and between agoraphobia and other phobias, few data are currently available on this topic. The risk for agoraphobia was initially noted to be significantly higher among parents and siblings of 60 agoraphobic patients than estimates of the population incidence.

A second family study, including non-anxious controls and their relatives, confirmed this familial aggregation of agoraphobia, showing that the morbidity risk for agoraphobia was significantly increased among relatives of agoraphobics but not the relatives of PD patients nor non-anxious subjects.