title: Test-retest reliability of the Danish Adult Reading Test in patients with comorbid psychosis and cannabis-use disorder.
abstract: BACKGROUND
  The New Adult Reading Test is a common instrument for assessing pre-morbid IQ for patients with, for instance, schizophrenia. However, test-retest reliability has not been established for patients dually diagnosed with psychosis and substance use disorder. Furthermore, test-retest reliability of the Danish adaptation has never been established in any population.
  
  
  OBJECTIVE
  To determine the test-retest reliability of the Danish Adult Reading Test (DART) (adapted from the National Adult Reading Test, NART) for patients dually diagnosed with psychosis and cannabis-use disorder.
  
  
  METHODS
  This was a secondary analysis of the CapOpus randomized trial. As part of the trial, 103 patients were randomized, and completed the DART up to three times. Pearson's r and pairwise t-tests were calculated.
  
  
  RESULTS
  DART score was independent of randomization, cannabis-use frequency and psychopathology. Scores at the last interview were slightly higher than at the first two. Correlation over time was very strong (0.8 < r <0.9) for all pairwise comparisons of interviews. Variations in DART scores and estimated pre-morbid IQ over time were sometimes of borderline statistical significance but not of clinical relevance.
  
  
  CONCLUSIONS
  DART and NART have high test-retest reliability, but apparently non-systematic, clinically irrelevant variation over time does occur.
  
  
  CONCLUSIONS
  The Danish adaptation of the New Adult Reading Test possesses good test-retest reliability, making it an appropriate choice for assessment of pre-morbid IQ, and in patients with dually diagnosed psychosis and cannabis-use disorder.
authors.affiliation: Copenhagen University Hospital, Mental Health Center Copenhagen, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark. Carsten.Rygaard.Hjorthoej@regionh.dk
authors.forename: Carsten Rygaard
authors.initials: CR
authors.lastname: Hjorthøj
authors.forename: Lone
authors.initials: L
authors.lastname: Vesterager
authors.forename: Merete
authors.initials: M
authors.lastname: Nordentoft
mesh_terms: D000328:Adult; D003718:Denmark; D017831:Diagnosis, Dual (Psychiatry); D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D002189:Marijuana Abuse / Q000503:physiopathology*; D011618:Psychotic Disorders / Q000150:complications / Q000175:diagnosis; D016032:Randomized Controlled Trials as Topic; D011932:Reading; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000503:physiopathology*; D055815:Young Adult