title: D-cycloserine enhancement of fear extinction is specific to successful exposure sessions: evidence from the treatment of height phobia.
abstract: BACKGROUND
  Whereas some studies have shown clear evidence for an augmentation effect of D-cycloserine (DCS) on exposure therapy for anxiety disorders, other studies have shown weak effects or no effect at all. Some preclinical data suggest that the DCS augmentation effect is moderated by the success of extinction learning. Therefore, we conducted a reanalysis of existing data to examine whether the effects of DCS on clinical outcome would vary as a function of response to the exposure session (i.e., exposure success).
  
  
  METHODS
  In a clinical trial, patients with height phobia received two sessions involving 30 minutes of virtual reality exposure therapy and were randomly assigned to a pill placebo (n = 14) or 50 mg of DCS (n = 15) immediately after each session.
  
  
  RESULTS
  Mixed-effects regression analysis showed that the effects of DCS administration on clinical improvement was moderated by the level of fear experienced just before concluding exposure sessions. Patients receiving DCS exhibited significantly greater improvement in symptoms relative to patients who received placebo when fear was low at the end of the exposure. In contrast, when end fear was still elevated, patients receiving DCS improved less compared with those receiving placebo.
  
  
  CONCLUSIONS
  D-cycloserine appears to enhance the benefits of exposure treatment when applied after a successful session, but it seems to have detrimental effects when administered after inadequate/unsuccessful exposure sessions.
authors: Department of Psychology, Southern Methodist University, Dallas, Texas 75206, USA. jsmits@smu.edu
authors: Jasper A J
authors: JA
authors: Smits
authors: David
authors: D
authors: Rosenfield
authors: Michael W
authors: MW
authors: Otto
authors: Mark B
authors: MB
authors: Powers
authors: Stefan G
authors: SG
authors: Hofmann
authors: Michael J
authors: MJ
authors: Telch
authors: Mark H
authors: MH
authors: Pollack
authors: Candyce D
authors: CD
authors: Tart
mesh_terms: D000328:Adult; D003523:Cycloserine / Q000627:therapeutic use*; D004311:Double-Blind Method; D005108:Extinction, Psychological / Q000187:drug effects*; D005239:Fear / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010698:Phobic Disorders / Q000188:drug therapy / Q000523:psychology / Q000534:rehabilitation; D012044:Regression Analysis; D012720:Severity of Illness Index; D063367:Virtual Reality Exposure Therapy / Q000379:methods*
chemical_list: D003523:Cycloserine