title: Contributions of ethnicity to differential item functioning of cannabis abuse and dependence symptoms.
abstract: OBJECTIVE
  Cannabis is the most widely used illicit drug in the United States, and as a result, it is associated with significant public health costs. The present study sought to investigate whether item response theory (IRT) methods could be used to identify meaningful differences in how cannabis abuse and dependence symptoms (determined by criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) function as indices of the severity of misuse across two ethnic groups: Native Americans and European Americans.
  
  
  METHODS
  Participants were drawn from two previously collected samples, a population of Native Americans living on contiguous reservations (n = 406) and the University of California at San Francisco Family Alcoholism Study (n = 728). Cannabis use disorder symptoms were assessed using the Semi-Structured Assessment for the Genetics of Alcoholism.
  
  
  RESULTS
  Exploratory factor analysis demonstrated that the cannabis abuse and dependence symptoms indexed a single latent trait measuring severity of cannabis use. IRT and multiple indicators multiple causes (MIMIC) analyses suggested meaningful differences in the functioning of these symptoms across ethnic groups. Withdrawal represented a more prevalent and less severe symptom among Native Americans relative to European Americans, whereas each of the cannabis abuse symptoms and a symptom assessing psychological and health problems resulting from cannabis use were less prevalent but more severe in Native Americans.
  
  
  CONCLUSIONS
  The findings suggest differences in how cannabis use disorders manifest in these populations and thus have implications for the assessment of these disorders as well as theories attempting to explain the increased rates of substance use diagnoses more generally among Native Americans living on reservations.
authors: Department of Psychological Sciences, University of Missouri, Columbia, Missouri, USA. gizeri@missouri.edu
authors: Ian R
authors: IR
authors: Gizer
authors: David A
authors: DA
authors: Gilder
authors: Philip
authors: P
authors: Lau
authors: Ting
authors: T
authors: Wang
authors: Kirk C
authors: KC
authors: Wilhelmsen
authors: Cindy L
authors: CL
authors: Ehlers
mesh_terms: D000293:Adolescent; D000328:Adult; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007198:Indians, North American / Q000706:statistics & numerical data*; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000208:ethnology; D008385:Marijuana Smoking / Q000453:epidemiology* / Q000208:ethnology; D008875:Middle Aged; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*; D055815:Young Adult
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