title: A comparative study of screening instruments and biomarkers for the detection of cannabis use.
abstract: BACKGROUND
  The aim of this study was to compare the usefulness of 3 different screening instruments (questionnaires) for the detection of cannabis use (CU) with biological markers in blood and hair.
  
  
  METHODS
  Ninety-four students were recruited in October 2013. Participants filled out the Severity of Dependence Scale (SDS), the CAGE-AID ("Cut down Annoyed Guilty Eye-opener"-Adapted to Include Drugs), and ProbCannabis-DT questionnaires concerning their possible CU. Blood and hair samples were taken and analyzed by gas chromatography-mass spectrometry. Logistic regression (Nagelkerke R(2)) and receiver operating characteristic (ROC) curve analyses were performed. THCCOOH (Δ(9)-tetrahydrocannabinoic acid) plasma of ≥5 ng/mL and THC (Δ(9)-tetrahydrocannabinol) hair concentrations of ≥0.1 and ≥0.02 ng/mg were used as the gold standard for CU. The questionnaire results were compared with different concentration ranges for THCCOOH in plasma (<5, 5-75, and >75 ng/mL, indicating the intensity of use) and THC in hair (≥0.02 ng/mg, ≥0.1 ng/mg).
  
  
  RESULTS
  The Nagelkerke R(2) for comparing the SDS, CAGE-AID, and ProbCannabis-DT with THCCOOH in plasma was 0.350, 0.489, and 0.335, respectively. The area under the ROC curve (95% confidence interval) was 0.772 (0.662-0.882), 0.797 (0.710-0.884), and 0.769 (0.669-0.870), respectively. Corresponding sensitivity/specificity were 70%/84%, 100%/59%, and 87%/67%, respectively. These values were similar to those compared to a 0.02 ng/mg THC cutoff in hair.
  
  
  CONCLUSIONS
  Moderate agreement was found between all questionnaires and biomarkers of CU. The CAGE-AID and probCannabis-DT questionnaires were very sensitive, but less specific. SDS was less sensitive, but more specific.
authors.affiliation: a Department of Clinical Chemistry, Microbiology and Immunology , Ghent University , Ghent , Belgium.
authors.forename: Paulien
authors.initials: P
authors.lastname: Meersseman
authors.affiliation: a Department of Clinical Chemistry, Microbiology and Immunology , Ghent University , Ghent , Belgium.
authors.forename: Simon
authors.initials: S
authors.lastname: Vanhoutte
authors.affiliation: b Department of Public Health , Ghent University , Ghent , Belgium.
authors.forename: Joris
authors.initials: J
authors.lastname: Van Damme
authors.affiliation: b Department of Public Health , Ghent University , Ghent , Belgium.
authors.forename: Lea
authors.initials: L
authors.lastname: Maes
authors.affiliation: c Department of Psychiatry and Medical Psychology , Ghent University , Ghent , Belgium.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Lemmens
authors.affiliation: c Department of Psychiatry and Medical Psychology , Ghent University , Ghent , Belgium.
authors.forename: Gunter
authors.initials: G
authors.lastname: Heylens
authors.affiliation: a Department of Clinical Chemistry, Microbiology and Immunology , Ghent University , Ghent , Belgium.
authors.forename: Alain G
authors.initials: AG
authors.lastname: Verstraete
mesh_terms: D015415:Biomarkers / Q000032:analysis / Q000097:blood; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000032:analysis* / Q000097:blood; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000097:blood* / Q000378:metabolism; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods*; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D015415:Biomarkers; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol
keywords: CAGE-AID; ProbCannabis-DT questionnaire; SDS; cannabis use; sensitivity; specificity