title: A marijuana screening inventory (experimental version): description and preliminary psychometric properties.
abstract: OBJECTIVE
  Marijuana use prevalence, culturally confusing messages about marijuana risks, assessment dilemmas, and current screening inadequacies justify developing a marijuana specific screening inventory for assessment purposes. This article describes the Marijuana Screening Inventory (MSI-X) and its preliminary psychometric reliability, factor analyses, and factor structure.
  
  
  METHODS
  The MSI-X was administered to a community sample of 420 Army reservists participating in substance abuse educational classes. Participants responded anonymously to the 39-item MSI-X. SPSS analyses were performed with 408 returned MSI-Xs from a sample of 49% males and 40% females.
  
  
  RESULTS
  Analyses revealed 61% smoked marijuana during their lifetime. Reliability of the MSI-X was .89. Exploratory factor analyses of 31 scored items by principal components and varimax rotation supported a nine-factor structure, explaining 65.8% of the variance, with all items loading > or = .30. Within the sample, 7.84% scored > or = 7 suggesting "at risk" with marijuana; 6.12% scored 4 to 6 "suggestive of risk"; 20.83% scored 1 to 3 reflecting "normal or experimental" use; and 65.4% scored 0 suggesting "no problem."
  
  
  CONCLUSIONS
  The reliability, variance explained, factor-loading matrix of the nine-factor MSI-X structure and clinically predetermined scoring ranges appear useful for screening marijuana use patterns. Factor-based subscales were derived from the factor-loading matrix and described as a base for future confirmatory factor analysis. Although the MSI-X version needs psychometric strengthening, it shows potential as a marijuana-specific screening inventory for use in general mental health and primary care settings.
mesh_terms: D000293:Adolescent; D000328:Adult; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D008403:Mass Screening / Q000295:instrumentation / Q000706:statistics & numerical data; D008875:Middle Aged; D015146:Midwestern United States; D008889:Military Personnel / Q000523:psychology; D025341:Principal Component Analysis; D011594:Psychometrics / Q000295:instrumentation*; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000295:instrumentation* / Q000706:statistics & numerical data; D014505:Urban Population