A family study of panic disorder.

In a family study of panic disorder, we collected data on 278 first-degree relatives of 41 probands with panic disorder and 262 relatives of 41 control probands. The morbidity risk for panic disorder was 17.3% in the first group, and an additional 7.4% were categorized as having probable panic disorder. Both rates were significantly higher than the respective rates in the control relatives, 1.8% and 0.4%. The risk of panic disorder in female subjects was twice that in male subjects. The rate of generalized anxiety disorder was the same in both groups of families. No other psychiatric disorders were increased in the families of patients with panic disorder. In a preliminary genetic analysis, we tested the single major locus and the multifactorial polygenic transmission models. Neither model was excluded by the data. We conclude that panic disorder is a familial disease that affects women twice as frequently as men and is not associated with an increased familial risk of other psychiatric conditions. Its method of transmission remains uncertain.