Evidence-based guidelines for interpretation of the Panic Disorder Severity Scale

Area of Science:

• Psychiatry
• Clinical Psychology
• Psychometrics

Background:

• The Panic Disorder Severity Scale (PDSS) shows potential as a global standard for panic disorder assessment.
• Establishing clear guidelines for interpreting PDSS scores and defining clinical change points (response, remission) is crucial for its clinical utility.

Purpose of the Study:

• To develop guidelines for interpreting PDSS scores in panic disorder patients.
• To define clinical change points, specifically "response" and "remission," using the PDSS.
• To establish correspondences between PDSS scores/changes and the Clinical Global Impression (CGI) scales.

Main Methods:

• Utilized individual patient data from two large randomized controlled trials for panic disorder (n=568).
• Administered the PDSS and CGI-Severity/Improvement scales to study participants.
• Employed equipercentile linking to correlate PDSS scores/changes with CGI measures.

Main Results:

• PDSS score interpretation varied based on the presence or absence of agoraphobia, with distinct ranges for "Normal" to "Markedly ill."
• Percentile changes in PDSS demonstrated a more linear relationship with CGI-Improvement than numeric changes.
• A decrease of 40-74% in PDSS was associated with "Much improved" on the CGI-Improvement scale.

Conclusions:

• Proposed definition for panic disorder "remission" as a PDSS score of five or less.
• Proposed definition for panic disorder "response" as a 40% or greater reduction in PDSS score.