Are there subtypes of panic disorder? An interpersonal perspective

Objective: Panic disorder (PD) is associated with significant personal, social, and economic costs. However, little is known about specific interpersonal dysfunctions that characterize the PD population. The current study systematically examined these interpersonal dysfunctions. Method: The present analyses included 194 patients with PD out of a sample of 201 who were randomized to cognitive-behavioral therapy, panic-focused psychodynamic psychotherapy, or applied relaxation training. Interpersonal dysfunction was measured with the Inventory of Interpersonal Problems-Circumplex (Horowitz, Alden, Wiggins, & Pincus, 2000). Results: Individuals with PD reported greater levels of interpersonal distress than that of a normative cohort (especially when PD was accompanied by agoraphobia), but lower than that of a cohort of patients with major depression. There was no single interpersonal profile that characterized PD patients. Symptom-based clusters (with vs. without agoraphobia) could not be discriminated on core or central interpersonal problems. Rather, as revealed by cluster analysis based on the pathoplasticity framework, there were 2 empirically derived interpersonal clusters among PD patients that were not accounted for by symptom severity and were opposite in nature: domineering-intrusive and nonassertive. The empirically derived interpersonal clusters appear to be of clinical utility in predicting alliance development throughout treatment: Although the domineering-intrusive cluster did not show any changes in the alliance throughout treatment, the nonassertive cluster showed a process of significant strengthening of the alliance. Conclusions: Empirically derived interpersonal clusters in PD provide clinically useful and nonredundant information about individuals with PD.