title: Crosswise Model to Assess Sensitive Issues: A Study on Prevalence of Drug Abuse Among University Students of Iran.
abstract: BACKGROUND
  Precise assessment of the prevalence of illicit drug use, face various methodological challenges.
  
  
  OBJECTIVE
  The current study aimed to investigate the prevalence of illicit drug use among students studying at Universities in Shahroud (Northeast of Iran) through crosswise method.
  
  
  METHODS
  Participants of this cross-sectional study were 1646 students at Universities in Shahroud. The data collection instrument was a questionnaire designed based on crosswise model (CM).
  
  
  RESULTS
  The results of the study showed that 19% of students used at least one kind of illicit drug and 14.9% used opium residue once in their life. Moreover, 3.5% of students used drug and 3% used opium residue during the last month; 40.3% of the students admitted that they fully understood the instruction of the questionnaire; 9.6% said that did not comprehend the instruction at all, and 38.1% believed they partly understood the instruction. The result showed that 33.7% of the students fully trusted, 39.8% partly trusted, and 18.4% poorly trusted this method. There was a significant relationship between comprehension level and trust in CM (P < 0.001).
  
  
  CONCLUSIONS
  This method can be appropriate to estimate sensitive issues; however, lack of understanding the method or doubting the confidentiality of the responses can lead to bias in the results. That is to say, if the instructions are introduced better, the level of trusting the method will increase and accordingly more reliable responses can be obtained. More studies under controlled conditions are required to interpret the findings of the current study better.
authors.affiliation: Center for Health Related Social and Behavioral Sciences Research, Shahroud University of Medical Sciences, Shahroud, IR Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Khosravi
authors.affiliation: Golestan Research Center of Psychiatry, Golestan University of Medical Sciences, Gorgan, IR Iran.
authors.forename: Seyed Abbas
authors.initials: SA
authors.lastname: Mousavi
authors.affiliation: Department of Social Medicine, Yasuj University of Medical Sciences, Yasuj, IR Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Chaman
authors.affiliation: Department of Biostatics, Mazandaran University of Medical Sciences, Sari, IR Iran.
authors.forename: Faride
authors.initials: F
authors.lastname: Khosravi
authors.affiliation: School of Public Health, Shahroud University of Medical Sciences, Shahroud, IR Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Amiri
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Shamsipour
keywords: Drug Abuse; Illicit Drug; Iran