Patterns of axis II comorbidity in early-onset versus late-onset panic disorder in Japan.

Early onset of psychiatric disorders has been reported to be associated with increased familial risk or more severe clinical symptoms. In this study, we specifically examine the association between clinical severity and early versus late onset in panic disorder. We hypothesize the existence of differences in rates of axis II disorders in these two groups that will relate to clinical severity. Subjects were a consecutive clinical case series of 105 panic disorder patients (age, 18.3 to 70.9 years). Thirty-one panic disorder patients were classified as early onset (age of onset < or = 25 years) and 74 as late onset (age of onset >25). We compared symptomatology and rates of comorbid axis II disorders (diagnosed by structured clinical interview) between the early- and the late-onset groups. We found a statistically significant increase in the number of suicide attempts and likelihood of comorbid axis II disorders in the early-onset group compared to the late-onset group. In logistic regression analyses, cluster B personality disorders (PDs), especially borderline and histrionic, were statistically significantly associated with the presence of suicide attempts. The following limitations are present: first, we have not taken into consideration comorbidity of other axis I disorders, especially major depression. Second, there is imprecision associated with efforts to date the onset of panic disorder retrospectively. We conclude that comorbid axis II disorders are more likely to occur in early-onset panic disorder patients. Cluster B PDs, especially borderline or histrionic, may be associated with a high frequency of suicide attempts in this group. In clinical practice, efforts to aggressively detect and treat axis II disorders in early-onset panic disorder patients are warranted.