title: Risk for marijuana-related problems among college students: an application of zero-inflated negative binomial regression.
abstract: METHODS
  This study examined the association between marijuana-related problems and social norms, impulsivity, and perceived use utility among 292 college students. Zero-inflated negative binomial regression was used to simultaneously predict expected nonusers as well as predict counts of reported marijuana-related problems among expected users. Gender, social norms, impulsivity, and perceived use utility were used to predict expected nonusers as well as number of marijuana-related problems among expected users.
  
  
  RESULTS
  Only social norms were associated with the prediction of zero-values. In contrast, only perceived use utility was associated with the prediction of number of marijuana-related problems.
  
  
  CONCLUSIONS
  Results generally are consistent with theories of the differential association of social-environmental and biopsychological variables with use and problems, respectively. Zero-inflated regression models are a useful strategy to examine risk behaviors with low base rates.
authors.affiliation: Department of Psychology, University of South Dakota, Vermillion, SD 57069, USA. jsimons@usd.edu
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Simons
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Neal
authors.forename: Raluca M
authors.initials: RM
authors.lastname: Gaher
mesh_terms: D000293:Adolescent; D000328:Adult; D000339:Affect; D007174:Disruptive, Impulse Control, and Conduct Disorders / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology*; D012044:Regression Analysis; D018570:Risk Assessment; D012307:Risk Factors; D012309:Risk-Taking; D013334:Students / Q000706:statistics & numerical data*; D014495:Universities