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Background: Given the growing legalization of recreational marijuana use and related increase in its prevalence in the United States, it is important to understand marijuana's appeal. We used a behavioral economic (BE) approach to examine whether the reinforcing properties of marijuana, including "demand" for marijuana, varied as a function of its perceived quality.Methods: Using an innovative, Web-based marijuana purchase task (MPT), a sample of 683 young-adult recreational marijuana users made hypothetical purchases of marijuana across three qualities (low, mid and high grade) at nine escalating prices per joint, ranging from $0/free to $20.Results: We used nonlinear mixed effects modeling to conduct demand curve analyses, which produced separate demand indices (e.g., Pmax, elasticity) for each grade of marijuana. Consistent with previous research, as the price of marijuana increased, marijuana users reduced their purchasing. Demand also was sensitive to quality, with users willing to pay more for higher quality/grade marijuana. In regression analyses, demand indices accounted for significant variance in typical marijuana use.Conclusions: This study illustrates the value of applying BE theory to young adult marijuana use. It extends past research by examining how perceived quality affects demand for marijuana and provides support for the validity of a Web-based MPT to examine the appeal of marijuana. Our results have implications for policies to regulate marijuana use, including taxation based on the quality of different marijuana products. [ABSTRACT FROM AUTHOR]

We examined relationships among personality (i.e., negative affectivity and conscientiousness), and use of licit and illicit substances in a sample of 421 college-aged social drinkers (52.7% women, 47.3% men). Results indicated significant relationships between personality and substance use as well as gender differences. Negative affectivity was related to greater illicit substance use, but not alcohol use or smoking. Conscientiousness was related to less alcohol use and smoking, which fully mediated relationships between conscientiousness and with less use of marijuana and other illicit substances. For women, conscientiousness was associated with less alcohol and smoking, compared to men. For men, alcohol use and smoking were more likely to lead to marijuana use, compared to women. Our findings support differential pathways from personality to substance use, and gender appears to be an important moderating factor. [Copyright &y& Elsevier]

Several theories posit that cannabis and other substances are used to reduce negative affect. This daily report study considered whether variations in positive and negative affect, reported each morning, contributed to the likelihood of cannabis use later that day. We also explored whether levels of positive and negative affect reported immediately after cannabis use improved, relative to that day's morning levels. The sample included 183 men and 183 women representing heterosexual, cannabis-using couples from the community. Participants made independent, daily reports of affect and cannabis use episodes for 30 consecutive days. Using multilevel modeling, we modeled men's and women's use of cannabis on a given day as a function of morning levels of positive, hostile, and anxious affect, accounting for partner cannabis use that day, and mean levels of positive and negative affect. Men and women were more likely to use cannabis on a given day when morning positive affect was lower than typical for the person and when partner used cannabis that day. Neither hostile nor anxious affect contributed to later use of cannabis. Immediately after cannabis use, positive affect increased, and hostile and anxious affect decreased relative to that day's morning levels. The improved affect immediately after use suggests a mechanism of positive reinforcement. [ABSTRACT FROM AUTHOR]

Abstract: Background: Previous laboratory-based research suggests that withdrawal from marijuana may cause increased aggression. It is unclear whether this finding extends beyond the laboratory setting to the general population of marijuana users. The purpose of this study was to test a cross-sectional association between marijuana withdrawal symptoms and aggression among a representative sample of U.S. adult marijuana users, and to test whether this association was moderated by previous history of aggression. Methods: Data were analyzed from the National Epidemiologic Survey on Alcohol and Related Conditions. Wave Two data (2004–2005) were used for all variables except for history of aggression, which was assessed during the Wave One interview (2001–2002). Two outcomes were examined: self-report general aggression and relationship aggression. Odds ratios for aggression based on withdrawal symptoms and the interaction between withdrawal symptoms and history of aggression were calculated using logistic regression, adjusting for covariates and accounting for the complex survey design. Results: Among marijuana users with a history of aggression, marijuana withdrawal was associated with approximately 60% higher odds of past year relationship aggression (p <0.05). There was no association between withdrawal symptoms and relationship aggression among those without a history of aggression, and no association with general aggression regardless of history of aggression. Conclusions: The findings from this study support the notion that laboratory-based increases in aggression due to marijuana withdrawal extend to the general population of marijuana users who have a previous history of aggression. [Copyright &y& Elsevier]