title: Validation of self-reported khat chewing amongst khat chewers: an exploratory study.
abstract: BACKGROUND
  Khat chewing amongst the UK communities originating from Yemen and the East African coast is suggested to create dependency through its main stimulant components (cathinone, norephedrine and norpseudoephedrine) on the central nervous system.
  
  
  OBJECTIVE
  To validate self-reported khat chewing behaviours by measuring levels of cathinone, norephedrine and norpseudoephedrine in saliva and to explore their associations with self-reported khat chewing dependency.
  
  
  METHODS
  Face-to-face interviews were conducted amongst 30 male UK-resident khat chewers. Saliva samples were collected from each participant and high-performance liquid chromatography (HPLC) employed to extract and quantify the levels of the biomarkers.
  
  
  RESULTS
  The mean (SD) for cathinone and the composite norephedrine and norpseudoephedrine levels were 33.93 (±39.20) and 29.28 (±26.32)μg/mL respectively. These biomarkers were significantly associated (p≤0.05) with khat chewing dependency.
  
  
  CONCLUSIONS
  Validation of self-reported khat chewing is possible. Khat chewing dependency correlates significantly with biomarker levels in saliva. Replication is required.
authors.affiliation: Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Institute of Dentistry, 4 Newark Street, London E1 2AT, UK. s.kassim@qmul.ac.uk
authors.forename: Saba
authors.initials: S
authors.lastname: Kassim
authors.forename: Aamenah
authors.initials: A
authors.lastname: Hawash
authors.forename: Atholl
authors.initials: A
authors.lastname: Johnston
authors.forename: Ray
authors.initials: R
authors.lastname: Croucher
mesh_terms: D000328:Adult; D000349:Africa / Q000208:ethnology; D000470:Alkaloids / Q000009:adverse effects / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D029754:Catha / Q000009:adverse effects / Q000737:chemistry*; D000697:Central Nervous System Stimulants / Q000009:adverse effects / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003617:Dangerous Behavior; D030881:Disclosure; D006801:Humans; D007407:Interviews as Topic / Q000592:standards*; D008297:Male; D008409:Mastication; D008875:Middle Aged; D010665:Phenylpropanolamine / Q000009:adverse effects / Q000032:analysis; D028321:Plant Preparations / Q000009:adverse effects / Q000737:chemistry; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D057566:Self Report / Q000592:standards*; D019966:Substance-Related Disorders; D006113:United Kingdom; D015006:Yemen / Q000208:ethnology
chemical_list: D000470:Alkaloids; D015415:Biomarkers; D000697:Central Nervous System Stimulants; D028321:Plant Preparations; C005331:norpseudoephedrine; D010665:Phenylpropanolamine; C023665:cathinone