Do comorbid personality disorders moderate panic-focused psychotherapy? An exploratory examination of the American Psychiatric Association practice guideline.

OBJECTIVE: The American Psychiatric Association (APA) practice guideline for panic disorder recommends psychodynamic psychotherapy for panic disorder patients with comorbid personality disorders. No data underlie this recommendation. This exploratory study assessed the moderating effect of personality disorder on psychodynamic and non-psychodynamic psychotherapy outcome.

METHOD: Forty-nine subjects with primary DSM-IV panic disorder were randomly assigned to 12 weeks of twice-weekly Panic-Focused Psychodynamic Psychotherapy or Applied Relaxation Training. The primary outcome measure was the Panic Disorder Severity Scale; the moderating effect of Axis II psychopathology on the Sheehan Disability Scale was also tested. The trial was conducted between February 2000 and January 2005.

RESULTS: Twenty-four subjects (49%) met DSM-IV criteria for a Structured Clinical Interview for DSM-IV Axis II Disorders-diagnosed personality disorder, of whom 19 (79%) had a cluster C diagnosis. Presence of a cluster C diagnosis moderated treatment outcome. Such subjects experienced greater improvements in Panic-Focused Psychodynamic Psychotherapy than subjects without cluster C comorbidity.

CONCLUSIONS: Despite its small sample size, this exploratory analysis provides initial preliminary evidence corroborating the APA practice guideline recommendation. Future panic disorder clinical trials should explore Axis II moderator effects.

CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov identifier NCT00128388.