Evaluating Medical Marijuana Dispensary Policies: Spatial Methods for the Study of Environmentally-Based Interventions

In 1996, California was the first state to pass a Compassionate Use Act allowing for the legal use of marijuana for medical purposes. Here we review several current policy and land use environmental interventions designed to limit problems related to the influx of medical marijuana dispensaries across California cities. Then we discuss the special challenges, solutions, and techniques used for studying the effects of these place-based policies. Finally, we present some of the advanced spatial analytic techniques that can be used to evaluate the effectiveness of environmental interventions, such as those related to reducing problems associated with the proliferation of medical marijuana dispensaries. Further, using data from a premise survey of all the dispensaries in Sacramento, this study will examine what characteristics and practices of these dispensaries are related to crime within varying distances from the dispensaries (e.g., 100, 250, 500, and 1,000 feet). We find that some security measures, such as security cameras and having a door man outside, implemented by medical marijuana dispensary owners might be effective at reducing crime within the immediate vicinity of the dispensaries.     

Social anxiety and problematic cannabis use: evaluating the moderating role of stress reactivity and perceived coping

Despite epidemiological reports indicating an association between social anxiety disorder (SAD) and cannabis use disorders (CUD), there is a paucity of research exploring the nature of this relationship. The present investigation examined potential moderators of this relationship that are consistent with a tension-reduction model of addiction. Specifically, physiological reactivity to stress and perceived coping with stress were evaluated as moderators of the relation between symptoms of SAD and CUD. Physiological (SCR) and subjective (perceived coping) responses to unpredictable white noise bursts were collected from non-clinical participants (n=123). Lifetime symptoms of CUD and anxiety disorders were assessed using a structured diagnostic interview. CUD symptomatology was associated with symptoms of SAD but not with symptoms of any other anxiety disorder. Only perceived coping to unpredictable stimuli moderated the relationship between SAD and CUD symptoms. Findings are discussed in the context of tension-reduction models of co-occurring social anxiety and problematic cannabis use.     

Self-Reported Use of Alcohol,Marijuana, and Hard Drugs and Aggression: A Structural Equation Modeling Analysis of an Internet Survey of Long-Term Marijuana Users

In the largest study to date investigating aggressive behavior among long-time adult concomitant marijuana and alcohol users, respondents completed an Internet survey on substance use and aggressive behavior. Aggressive acts following alcohol consumption were more frequent than aggressive acts following marijuana consumption. Structural equation modeling demonstrated that there was no relationship between marijuana and aggression once recent alcohol use, hard drug history, gender, and age were taken into account. Alcohol use and history of hard drug use were associated with increased aggression. It also appears that increased aggression among males is partially mediated by alcohol use. This model fit the data better than plausible alternative models. Although the sample characteristics limit the generalizability of these findings, our data suggest that marijuana use does not lead to aggressive behavior in adults, even among frequent, long-time users.     

Religiosity and adolescent marijuana use

Among adolescents, religiosity has been associated with lower rates of marijuana use, though few studies have examined its impact on the perceived risk of use. There is strong support that perceived risk of using marijuana is negatively correlated with the frequency of use. We examined the relationship among religiosity, perceived risk, and marijuana use from a national survey of adolescents that contained questions about lifetime, weekly, and past month substance use, social support, religious involvement and attitudes, and perceived riskiness of use. We tested a structural equation model of relationships among latent variables of religiosity and perceived risk, and an observed variable of total days of marijuana use in the past 12 months. Results indicated the model was a good fit to the data and described a mediating relationship of perceived risk of use between religiosity and marijuana use. Implications for leveraging religiosity in prevention of substance use are discussed.     

Prediction of Cannabis Use Disorder Between Childhood and Young Adulthood Using the Child Behavior Checklist

A prospective investigation was conducted to evaluate the accuracy of internalizing and externalizing traits measured at ages 10–12 for predicting a DSM-IV diagnosis of cannabis use disorder manifest by age 22. The sample consisted of 189 boys rated on the Child Behavior Checklist (CBCL) by their biological mothers. The results indicated that externalizing but not internalizing disturbance was a significant predictor of cannabis use disorder. Moreover, a construct capturing their common variance did not predict cannabis use disorder better than externalizing behavior alone.     

Cultural predictors of future intention to drive under the influence of cannabis (DUIC)

This study examines the influence that traffic safety culture has on the intention to drive under the influence of cannabis (DUIC) in the next six months. Here, traffic safety culture is defined as “the values and beliefs shared among groups of road users and stakeholders that influence their decisions to behave in ways that improve traffic safety.” To operationalize this definition, a 14-item survey was developed with a binary response format (yes, no) based on a behavioral model predicting intentional DUIC. The sampling plan collected data from drivers at the roadside with the goal of obtaining a Friday daytime and weekend nighttime sample representative of drivers across Washington State (n = 416).The results showed only a small percentage of randomly surveyed drivers in Washington State reported future intention to DUIC (45/416 = 11%). The intention of this small group could be reliably predicted based on certain aspects of their shared culture. Notably, drivers who shared the attitude that DUIC is enjoyable were 3.5 times more likely to report the intention to DUIC in the next six months. Conversely, drivers who shared the belief that cannabis impairs performance and the injunctive norm that people important to them would be disappointed were more than twice as likely not to report future intention to DUIC. Interestingly, the possession of a medical card for cannabis treatment influenced the effects of culture on DUIC intention. The results of this study suggest that strategies that can change DUIC culture amongst at-risk drivers may be effective in reducing such behaviors.     

Neurocognitive correlates of white matter quality in adolescent substance users

Background

Progressive myelination during adolescence implicates an increased vulnerability to neurotoxic substances and enduring neurocognitive consequences. This study examined the cognitive manifestations of altered white matter microstructure in chronic marijuana and alcohol-using (MJ + ALC) adolescents.

Methods

Thirty-six MJ + ALC adolescents (ages 16–19) and 36 demographically similar controls were evaluated with diffusion tensor imaging (Bava et al., 2009) and neurocognitive tests. Regions of group difference in fractional anisotropy (FA) and mean diffusivity (MD) were analyzed in relation to cognitive performance.

Results

In users, lower FA in temporal areas related to poorer performance on attention, working memory, and speeded processing tasks. Among regions where users had higher FA than controls, occipital FA was positively associated with working memory and complex visuomotor sequencing, whereas FA in anterior regions was negatively associated with verbal memory performance.

Conclusions

Findings suggest differential influences of white matter development on cognition in MJ + ALC using adolescents than in non-using peers. Neuroadaptation may reflect additive and subtractive responses to substance use that are complicated by competing maturational processes.     

The Effects of Cumulative Risks and Promotive Factors on Urban Adolescent Alcohol and Other Drug Use: A Longitudinal Study of Resiliency

Resiliency theory provides a conceptual framework for studying why some youth exposed to risk factors do not develop the negative behaviors they predict. The purpose of this study was to test compensatory and protective models of resiliency in a longitudinal sample of urban adolescents (80% African American). The data were from Years 1 (9th grade) and 4 (12th grade). The study examined effects of cumulative risk and promotive factors on adolescent polydrug use including alcohol, tobacco and marijuana. Cumulative measures of risk/promotive factors represented individual characteristics, peer influence, and parental/familial influences. After controlling for demographics, results of multiple regression of polydrug use support the compensatory model of resiliency both cross-sectionally and longitudinally. Promotive factors were also found to have compensatory effects on change in adolescent polydrug use. The protective model of resiliency evidenced cross-sectionally was not supported in longitudinal analysis. The findings support resiliency theory and the use of cumulative risk/promotive measures in resiliency research. Implications focused on utilizing multiple assets and resources in prevention programming are discussed.     

Risk and protective factors for marijuana use and problems with use in a national sample of female Ecuadorian secondary school students

This study investigated risk and protective factors for marijuana use and problems with use in Ecuadorian girls in an attempt to inform this growing problem. Female secondary school students (N = 16,310; M = 15.02, SD = 1.73 years) who completed the 2016 national survey of drug use participated. The likelihood of lifetime marijuana use, reported by 7.3% of the sample, was predicted by older age, greater perceived access to marijuana and affiliation with tobacco- and marijuana-using peers; aspects of parental monitoring and perceived physical safety in and around school were negatively related to the probability of use. Among girls reporting any marijuana use, age, frequency of past year use, ease of access and affiliation with marijuana-using peers was positively associated with marijuana use problems. These data support the roles of both parents and communities in reducing marijuana use among Ecuadorian girls and highlight the important role of peer influence.     

Associations between Marijuana Use During Emerging Adulthood and Aspects of the Significant Other Relationship in Young Adulthood

We used a prospective design to examine the association of marijuana use during the transition from late adolescence to early adulthood with reported relationship quality with significant other in the mid- to late twenties. The community-based sample consisted of 534 young adults (mean age=27) from upstate New York. The participants were interviewed at four points in time at mean ages 14, 16, 22, and 27 years. Marijuana use during the transition from late adolescence to early adulthood was associated with less relationship cohesion and harmony, and with more relationship conflict with control on variables reflecting the participants’ early interpersonal adjustment and the quality of the relationships with their parents. Our findings suggest that marijuana use during emerging adulthood predicts diminished relationship quality with a partner in the mid- to late twenties.