Reliability and validity of the Panic Disorder Severity Scale: replication and extension

Abstract

The Panic Disorder Severity Scale (PDSS) is a recently developed seven-item instrument to rate overall severity of Panic Disorder. The scale has previously shown good psychometric properties in a sample of Panic Disorder patients with no more than mild agoraphobia. The purpose of this paper is to confirm reliability and validity, to provide an estimate of a cut-score discriminating the presence or absence of current DSM-IV Panic Disorder, and to determine the factor structure of the instrument. Procedures: 104 psychiatric outpatients, including 54 with current Panic Disorder, underwent structured diagnostic assessment and the PDSS interview. The PDSS was repeated within 3–17 days. Results: we confirmed reliability and validity of the instrument and found a one-factor solution fit the data. A cut-off score of eight identifies patients with current panic with a sensitivity of 83.3%, and a specificity of 64%. Conclusion: the PDSS is a simple, reliable instrument for use in Panic Disorder studies. A cut-score of eight may be useful as a tool to screen patients in settings such as primary care, for diagnosis-level symptoms.