Objective: Psychiatric classification is still a topic of considerable discussion and debate in spite of major advances in the past two decades. The debate involves categorical versus dimensional approaches, cutoff numbers of symptoms to define a case, degree of impairment, objective diagnostic criteria versus more theoretically based criteria, episodic versus trait-like symptoms, and the role of atypical and subclinical symptoms. All of these issues have been raised for the anxiety disorders and depression. This article presents the conceptualization of a relatively novel and testable approach to the diagnosis and classification of panic and agoraphobia, the panic-agoraphobic spectrum, and pilot data on a new questionnaire to assess it.
Method: Pilot testing of the Panic-Agoraphobic Spectrum Questionnaire was undertaken with 100 inpatients who had lifetime diagnoses of panic disorder, unipolar depression, comorbid panic and unipolar depressive disorders, or an eating disorder. The instrument emphasizes impairment related to 144 behaviors and experiences in seven panic-agoraphobic symptom domains.
Results: Patients with panic disorder scored highest on the questionnaire, and those with comorbid depression showed even greater severity of illness. The scores of the patients with eating disorders and of the depressed patients differed from those of the other groups but also differed from 0.
Conclusions: The spectrum model of panic and agoraphobia is a flexible and comprehensive means of describing this clinical complex. The proposed model, complementary to the categorical approach, presumably expresses a unitary pathophysiology. Its usefulness is discussed in terms of its value for patient-therapist communication, outcome measures, identification of subtle personality traits, and subtyping of patients for research and treatment.