title: A systematic review of predictors and moderators of improvement in cognitive-behavioral therapy for panic disorder and agoraphobia.
abstract: BACKGROUND
  Despite the considerable efficacy of cognitive-behavioral therapy (CBT) for panic disorder (PD) and agoraphobia, a substantial minority of patients fail to improve for reasons that are poorly understood.
  
  
  OBJECTIVE
  The aim of this study was to identify consistent predictors and moderators of improvement in CBT for PD and agoraphobia.
  
  
  METHODS
  A systematic review and meta-analysis of articles was conducted using PsycInfo and PubMed. Search terms included panic, agoraphobi*, cognitive behavio*, CBT, cognitive therapy, behavio* therapy, CT, BT, exposure, and cognitive restructuring.
  
  
  METHODS
  Studies were limited to those employing semi-structured diagnostic interviews and examining change on panic- or agoraphobia-specific measures.
  
  
  METHODS
  The first author extracted data on study characteristics, prediction analyses, effect sizes, and indicators of study quality. Interrater reliability was confirmed.
  
  
  RESULTS
  52 papers met inclusion criteria. Agoraphobic avoidance was the most consistent predictor of decreased improvement, followed by low expectancy for change, high levels of functional impairment, and Cluster C personality pathology. Other variables were consistently unrelated to improvement in CBT, understudied, or inconsistently related to improvement.
  
  
  CONCLUSIONS
  Many studies were underpowered and failed to report effect sizes. Tests of moderation were rare.
  
  
  CONCLUSIONS
  Apart from agoraphobic avoidance, few variables consistently predict improvement in CBT for PD and/or agoraphobia across studies.
authors.affiliation: Department of Psychology, University of Pennsylvania, 3720 Walnut Street, Philadelphia, PA 19104, United States. Electronic address: eliora@psych.upenn.edu.
authors.forename: Eliora
authors.initials: E
authors.lastname: Porter
authors.affiliation: Department of Psychology, University of Pennsylvania, 3720 Walnut Street, Philadelphia, PA 19104, United States.
authors.forename: Dianne L
authors.initials: DL
authors.lastname: Chambless
mesh_terms: D000379:Agoraphobia / Q000628:therapy*; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods*; D016584:Panic Disorder / Q000628:therapy*
keywords: Agoraphobia; CBT; Moderators; Panic disorder; Predictors; Treatment outcome