Risk for Marijuana-Related Problems among College Students: An Application of Zero-Inflated Negative Binomial Regression

Abstract

Method: 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.

Keywords:

• Marijuana
• impulsivity
• social norms
• expected utility
• drug abuse
• affect