Comparison of primary and secondary panic disorder: a preliminary report.

We examined the onsets of comorbid psychiatric disorders in patients with panic disorder (PD) (N = 54). In 42 patients (77.8%), PD was preceded by another psychiatric condition (secondary PD group), while in 12 patients (22.2%), PD occurred first or was the only diagnosed mental disorder (primary PD group). Patients with primary and secondary PD did not differ with respect to demographic variables, mean ages of onset of PD, mean duration of PD, number of patients with a personality disorder, and number of patients with different DSM-III-R subtypes of PD. Except for the anger and sleep scales of the Hopkins Symptom Checklist 90, patients with primary PD had significantly less self-rated psychopathology; they also displayed less extensive phobic avoidance, and had a lower rate of current psychiatric comorbidity. These findings are discussed in light of the value of the concepts of comorbidity and primary/secondary dichotomy.