The familial aggregation of panic disorder by source of proband ascertainment.

Estimates of familial aggregation of psychiatric disorder obtained from relatives of probands ascertained in treatment settings may differ from estimates obtained from relatives of probands ascertained from the general population. In this paper we investigate this hypothesis for panic disorder, by comparing the degree of familial aggregation of panic disorder in relatives of probands with panic disorder ascertained from either a specialty anxiety clinic, a specialty depression clinic or a population survey, respectively. Results for panic disorder do not suggest that familial rates are associated with source of proband ascertainment. Results show that the rates of panic disorder in relatives were similar by proband source. This suggests that familial rates of panic disorder are not associated with proband ascertainment and that selecting probands from treatment clinics rather than from the general population does not necessarily lead to greater estimates of familial aggregation of panic disorder. Further research is needed to determine if this finding can be generalized to other psychiatric disorders.