Objective: The authors investigated the relation of age at onset of panic disorder to liability to panic disorder and agoraphobia.
Method: Two hundred thirty-one outpatients with panic disorder were compared with 131 surgical outpatients on demographic variables and familial risk of psychiatric disorders. The distribution of patients' ages at onset of panic disorder and several covariates were entered in a stepwise survival analysis.
Results: The patients with panic disorder had a significantly higher rate of childhood separation anxiety disorder and higher familial risks of panic disorder/panic disorder with agoraphobia and alcoholism. A family history of panic disorder with agoraphobia and the presence of childhood separation anxiety disorder influenced age at onset of panic disorder.
Conclusions: Age at onset of panic disorder may reflect genetic penetrance, and separation anxiety disorder may be an individual predictor of earlier onset of panic disorder.