title: Cannabidiol enhances consolidation of explicit fear extinction in humans.
abstract: BACKGROUND
  Whilst Cannabidiol (CBD), a non-psychotomimetic cannabinoid, has been shown to enhance extinction learning in rats, its effects on fear memory in humans have not previously been studied.
  
  
  OBJECTIVE
  We employed a Pavlovian fear-conditioning paradigm in order to assess the effects of CBD on extinction and consolidation.
  
  
  METHODS
  Forty-eight participants were conditioned to a coloured box (CS) with electric shocks (UCS) in one context and were extinguished in a second context. Participants received 32 mg of CBD either following before or after extinction in a double-blind, placebo-controlled design. At recall, 48 h later, participants were exposed to CSs and conditioning contexts before (recall) and after (reinstatement) exposure to the UCS. Skin conductance and shock expectancy measures of conditioned responding were recorded throughout.
  
  
  RESULTS
  Successful conditioning, extinction and recall were found in all three treatment groups. CBD given post-extinction enhanced consolidation of extinction learning as assessed by shock expectancy. CBD administered at either time produced trend level reduction in reinstatement of autonomic contextual responding. No acute effects of CBD were found on extinction.
  
  
  CONCLUSIONS
  These findings provide the first evidence that CBD can enhance consolidation of extinction learning in humans and suggest that CBD may have potential as an adjunct to extinction-based therapies for anxiety disorders.
authors.affiliation: Clinical Psychopharmacology Unit, University College London, Gower Street, London, WC1E 7HB, UK. ravi.k.das@gmail.com
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Das
authors.forename: Sunjeev K
authors.initials: SK
authors.lastname: Kamboj
authors.forename: Mayurun
authors.initials: M
authors.lastname: Ramadas
authors.forename: Kishoj
authors.initials: K
authors.lastname: Yogan
authors.forename: Vivek
authors.initials: V
authors.lastname: Gupta
authors.forename: Emily
authors.initials: E
authors.lastname: Redman
authors.forename: H Valerie
authors.initials: HV
authors.lastname: Curran
authors.forename: Celia J A
authors.initials: CJ
authors.lastname: Morgan
mesh_terms: D002185:Cannabidiol / Q000494:pharmacology*; D003214:Conditioning, Classical / Q000187:drug effects*; D004311:Double-Blind Method; D004597:Electroshock; D005108:Extinction, Psychological / Q000187:drug effects*; D005239:Fear / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D013997:Time Factors
chemical_list: D002185:Cannabidiol