Development of a brief diagnostic screen for panic disorder in primary care.

Objective: The purpose of this study was to determine the utility of a brief screening tool for panic disorder in the primary care setting.
Methods: A total of 1476 primary care outpatients in three primary care medical clinics on the West Coast of the United States were studied. Patients completed a brief self-report measure, the five-item Autonomic Nervous System Questionnaire (ANS), while in the waiting room. The presence of DSM-IV panic disorder was subsequently determined in groups of "screen-positive" and "screen-negative" subjects using the Composite International Diagnostic Interview. A subset of patients (N = 511) also completed the 21-item Beck Anxiety Inventory. Indices of diagnostic utility were calculated using receiving operating characteristic analyses to guide the selection of optimal cutoff levels.
Results: The two-question version of the ANS had excellent sensitivity (range = 0.94-1.00 across the three clinic sites) and negative predictive value (0.94-1.00) but low specificity (0.25-0.59) and positive predictive value (range 0.18-0.40). The three- and five-question versions of the ANS had only modestly improved specificity, and this was achieved at the cost of reduced sensitivity and increased respondent burden to complete the questionnaire. The 21-item Beck Anxiety Inventory had maximal clinical utility at a cutoff level of > or =20, but sensitivity was lower than desirable for a screening instrument (0.67).
Conclusions: The two-question version of the ANS shows promise as a screening instrument for panic disorder in the primary care setting.