Bringing perspective to illicit markets: estimating the size of the U.S. marijuana market

Impact of Marijuana Use on Lung Health

The widespread use of marijuana in the context of increasing legalization has both short- and long-term health implications. Although various modes of marijuana use-smoked, vaped, or ingested-may lead to a wide scope of potential systemic effects, we focus here on inhalational use of marijuana as the most common mode with the lung as the organ that is most directly exposed to its effects. Smoked marijuana has been associated with symptoms of chronic bronchitis and histopathologic changes in airway epithelium, but without consistent evidence of long-term decline in pulmonary function. Its role in immunomodulation, both for risk of infection and protection against a hyperinflammatory host response to infection, has been suggested in animal models and in vitro without conclusive extrapolation to humans. Marijuana smoke contains carcinogens like those found in tobacco, raising concern about its role in lung cancer, but evidence is mixed and made challenging by concurrent tobacco use. Vaping may offer a potential degree of harm reduction when compared with smoking marijuana with reduction of exposure to several toxins, including carbon monoxide, and reduction in chronic respiratory symptoms. However, these potential benefits are counterbalanced by risks including vaping-associated lung injury, potentially more intense drug exposure, and other yet not well-understood toxicities. As more states legalize marijuana and the federal government considers changing this from a Schedule I to a Schedule III controlled substance, we anticipate an increase in prospective medical studies concerning the risks related to marijuana use. This review is based on currently available data concerning the impact of inhaled marijuana on lung health.

Most recent, modal, or median heroin purchase: Does it matter when estimating market size?

BACKGROUND

Assessing the size of illicit drug markets is an important activity of many government agencies; however, the expenditure-based method for estimating market size relies on the relatively untested assumption that the cash value of the most recent purchase is representative of the average purchase amount. Using panel data, we test the representativeness of the most recent, modal and median purchase compared to the average purchase amount.

METHODS

Data were drawn from a prior study that collected daily transaction-level purchase data from a sample of 120 people who were using heroin regularly. The same study participants completed two distinct two-week waves of data collection, separated by six months. T-tests and bootstrapping were used to detect differences within each wave between the average cash value of participant heroin purchases and the cash value of their most recent, modal and median heroin purchases.

RESULTS

In both waves, we found (a) no evidence that the expected value of the most recent purchase differs from the expected value of the average purchase, and (b) the expected values of the modal and median purchases are smaller than the expected value of the average purchase. These results imply that estimates of total market size based on the modal or median purchase will suffer from a significant downward bias, but that estimates based on the most recent purchase will be unbiased.

CONCLUSIONS

We provide evidence in support of using the most recent (but not the modal or the median) purchase to estimate market size for heroin.

Heroin use cannot be measured adequately with a general population survey

BACKGROUND

Globally, heroin and other opioids account for more than half of deaths and years-of-life-lost due to drug use and comprise one of the four major markets for illegal drugs. Having sound estimates of the number of problematic heroin users is fundamental to formulating sound health and criminal justice policies. Researchers and policymakers rely heavily upon general population surveys (GPS), such as the US National Survey on Drug Use and Health (NSDUH), to estimate heroin use, without confronting their limitations. GPS-based estimates are also ubiquitous for cocaine and methamphetamine, so insights pertaining to GPS for estimating heroin use are also relevant for those drug markets.

ANALYSIS

Four sources of potential errors in NSDUH are assessed: selective non-response, small sample size, sampling frame omissions and under-reporting. An alternative estimate drawing on a variety of sources including a survey of adult male arrestees is presented and explained. Other approaches to prevalence estimation are discussed.

FINDINGS

Under-reporting and selective non-response in NSDUH are likely to lead to substantial underestimation. Small sample size leads to imprecise estimates and erratic year-to-year fluctuations. The alternative estimate provides credible evidence that NSDUH underestimates the number of frequent heroin users by at least three-quarters and perhaps much more.

IMPLICATIONS

GPS, even those as strong as NSDUH, are doomed by their nature to estimate poorly a rare and stigmatized behavior concentrated in a hard-to-track population. Although many European nations avoid reliance upon these surveys, many others follow the US model. Better estimation requires models that draw upon a variety of data sources, including GPS, to provide credible estimates. Recent methodological developments in selected countries can provide guidance. Journals should require researchers to critically assess the soundness of GPS estimates for any stigmatized drug-related behaviors with low prevalence rates.

Locating Medical and Recreational Cannabis Outlets for Research Purposes: Online Methods and Observational Study

Background

An increasing number of states have laws for the legal sale of recreational and medical cannabis out of brick-and-mortar storefront locations. Given the proliferation of cannabis outlets and their potential for impact on local economies, neighborhood structures, and individual patterns of cannabis use, it is essential to create practical and thorough methods to capture the location of such outlets for research purposes. However, methods used by researchers vary greatly between studies and often do not include important information about the retailer’s license status and storefront signage.

Objective

The aim of this study was to find methods for locating and observing cannabis outlets in Los Angeles County after the period when recreational cannabis retailers were granted licenses and allowed to be open for business.

Methods

The procedures included searches of online cannabis outlet databases, followed by methods to verify each outlet’s name, address, license information, and open status. These procedures, conducted solely online, resulted in a database of 531 outlets. To further verify each outlet’s information and collect signage data, we conducted direct observations of the 531 identified outlets.

Results

We found that 80.9% (430/531) of these outlets were open for business, of which 37.6% (162/430) were licensed to sell cannabis. Unlicensed outlets were less likely to have signage indicating the store sold cannabis, such as a green cross, which was the most prevalent form of observed signage. Co-use of cannabis and tobacco/nicotine has been found to be a substantial health concern, and we observed that 40.6% (175/430) of cannabis outlets had a tobacco/nicotine outlet within sight of the cannabis outlet. Most (350/430, 81.4%) cannabis outlets were located within the City of Los Angeles, and these outlets were more likely to be licensed than outlets outside the city.

Conclusions

The findings of this study suggest that online searches and observational methods are both necessary to best capture accurate and detailed information about cannabis outlets. The methods described here can be applied to other metropolitan areas to more accurately capture the availability of cannabis in an area.

Policy analysis and implications of establishing the Caribbean Cannabis Economy (CCE): lessons from Jamaica

Purpose

The purpose of this paper is to explore the effects of legislative amendments to the Dangerous Drugs Act in 2015 and the establishment of a Cannabis Licensing Authority (CLA) in Jamaica as the first Caribbean country to decriminalize cannabis and attempt to establish a medical cannabis industry. The research also attempts to understand the perception of key industry players and interest groups to the existing regulatory framework in Jamaica.

Design/methodology/approach

The research reviews local and global trends, the developments in cannabis legislation and conducts questionnaires as well as semi-structured interviews to get feedback from key industry stakeholders and interest groups.

Findings

The findings suggest that there is a lack of confidence in the CLA in Jamaica, who are faced with the task of balancing the emerging medical cannabis industry and formalizing the existing illegal cannabis trade. There appears to be inconsistencies and lack of coordination between the associated ministries, departments and agencies. The CLA in Jamaica has established two separate cannabis models that appear to be incoherent in their approach to policy. On the one hand they are regulating cultivation, processing and supply, and on the other hand, the law remains unclear about the purchase or consumption of cannabis and its by-products.

Practical implications

Countries must learn from Jamaica’s experience if they wish to effectively establish a medical cannabis industry and legitimize existing illegal cannabis economic activities. These countries must ensure they tailor fit the approach of their CLAs to minimize any negative perception from industry players. Laws established to facilitate linkages from the cultivation to processing to packaging to transportation to retail must also include clear laws surrounding the purchase and consumption of cannabis. Jamaica has a far way to go and must continue to learn from other countries and states, for example, Holland, Spain and Uruguay, while at the same time learning from itself.

Originality/value

This paper is novel as it addresses the transition of the legislative process in Jamaica. It also serves as lesson for other countries that seek to engage in the development of their cannabis industries.

Exploring the perils of cross-national comparisons of drug prevalence: The effect of survey modality

BACKGROUND

There is significant interest in comparing countries on many different indicators of social problems and policies. Cross-national comparisons of drug prevalence and policies are often hampered by differences in the approach used to reach respondents and the methods used to obtain information in national surveys. The paper explores how much these differences could affect cross-country comparisons.

METHODS

This study reports prevalence of drug use according to the most recent national household survey and then adjusts estimates as if all national surveys used the same methodology. The analysis focuses on European countries for which the European Monitoring Centre for Drugs and Drug Addiction reports data, the United States, Canada, and Australia. Adjustment factors are based on US data.

FINDINGS

Adjusting for modality differences appears likely to modestly affect the rankings of countries by prevalence, but to an extent that could be important for comparisons. For example, general population surveys suggest that the US had some of the highest cannabis and cocaine prevalence rates circa 2012, but this is partially driven by the use of a modality known to produce higher prevalence estimates. This analysis shows that country rankings are partly an artifact of the mode of interview used in national general population surveys.

CONCLUSIONS

Our preliminary efforts suggest that cross-national prevalence comparisons, policy analyses and, other projects such as estimating the global burden of disease could be improved by adjusting estimates from drug use surveys for differences in modality. Research is needed to create more authoritative adjustment factors.

The effect of BLA GABA(A) receptors in anxiolytic-like effect and aversive memory deficit induced by ACPA

The roles of GABAergic receptors of the Basolateral amygdala (BLA) in the cannabinoid CB1 receptor agonist (arachydonilcyclopropylamide; ACPA)-induced anxiolytic-like effect and aversive memory deficit in adult male mice were examined in elevated plus-maze task. Results showed that pre-test intra-peritoneal injection of ACPA induced anxiolytic-like effect (at dose of 0.05 mg/kg) and aversive memory deficit (at doses of 0.025 and 0.05 mg/kg). The results revealed that Pre-test intra-BLA infusion of muscimol (GABA_A receptor agonist; at doses of 0.1 and 0.2 µg/mouse) or bicuculline (GABA_A receptor antagonist; at all doses) impaired and did not alter aversive memory, respectively. All previous GABA agents did not have any effects on anxiety-like behaviors. Interestingly, pretreatment with a sub-threshold dose of muscimol (0.025 µg/mouse) and bicuculline (0.025 µg/mouse) did not alter anxiolytic-like behaviors induced by ACPA, while both drugs restored ACPA-induced amnesia. Moreover, muscimol or bicuculline increased and decreased ACPA-induced locomotor activity, respectively. Finally the data may indicate that BLA GABA_A receptors have critical and different roles in anxiolytic-like effect, aversive memory deficit and locomotor activity induced by ACPA.

Cocaine's fall and marijuana's rise: questions and insights based on new estimates of consumption and expenditures in US drug markets

AIMS

Drug policy strategies and discussions often use prevalence of drug use as a primary performance indicator. However, three other indicators are at least as relevant: the number of heavy users, total expenditures and total amount consumed. This paper stems from our efforts to develop annual estimates of these three measures for cocaine (including crack), heroin, marijuana and methamphetamine in the United States.

METHODS

The estimates exploit complementary strengths of a general population survey (National Survey on Drug Use and Health) and both survey and urinalysis test result data for arrestees (Arrestee Drug Abuse Monitoring Program), supplemented by many other data sources.

RESULTS

Throughout the 2000s US drug users spent in the order of $100 billion annually on these drugs, although the spending distribution and use patterns changed dramatically. From 2006 to 2010, the amount of marijuana consumed in the United States probably increased by more than 30%, while the amount of cocaine consumed in the United States fell by approximately 50%. These figures are consistent with supply-side indicators, such as seizures and production estimates. For all the drugs, total consumption and expenditures are driven by the minority of users who consume on 21 or more days each month.

CONCLUSIONS

Even for established drugs, consumption can change rapidly. The halving of the cocaine market in five years and the parallel (but independent) large rise in daily/near-daily marijuana use are major events that were not anticipated by the expert community and raise important theoretical, research, and policy issues.

How much of the cocaine market are we missing? Insights from respondent-driven sampling in a mid-sized American city

BACKGROUND

Studying markets for illegal drugs is important, but difficult. Data usually come from a selected subset of consumers, such as arrestees, treatment clients, or household survey respondents. There are rarely opportunities to study how such groups may differ from other market participants or how much of total consumption they represent.

METHODS

This paper uses respondent-driven sampling (RDS) of drug users in a mid-sized American city to estimate the shares of cocaine (powder and crack) users and expenditures that are attributable to different combinations of these groups.

RESULTS

We find that those arrested in the last year accounted for 34% of past-month cocaine users and 40% of past-week cocaine spending in the RDS sample. Augmenting past-year arrestees with those who received treatment in the past year increases these values to 44% (users) and 55% (spending).

CONCLUSIONS

Our results suggest that estimates based only on people who were arrested and/or treated in the past year would have to be inflated by 100-200% to capture the market totals. Adding those who own or rent their place of residence increased coverage in this study to 76% (users) and 81% (spending), suggesting that in theory the inflation factor could be reduced to 23-32% by supplementing data on arrestees and treatment populations with household data, although in practice rates of under-reporting by survey respondents may make coverage (sampling frame) a secondary concern for household surveys.

The effects of purchasing alcohol and marijuana among adolescents at-risk for future substance use

BACKGROUND

Among high-risk youth, those who may be at increased risk for adverse alcohol and other drug (AOD) use outcomes may benefit from targeted prevention efforts; how youth acquire AOD may provide an objective means of identifying youth at elevated risk.

METHODS

We assessed how youth acquired alcohol and marijuana (purchasing vs. other means), demographics, AOD behaviors/consequences, and environment among adolescents referred to a diversion program called Teen Court (N = 180) at two time points (prior to the program and 180 days from baseline). Participants were predominantly White and Hispanic/Latino(a).

RESULTS

In cross-sectional analyses among alcohol and marijuana users, purchasing marijuana was associated with more frequent marijuana use and consequences, time spent around teens who use marijuana, higher likelihood of substance use disorders, and lower resistance self-efficacy compared to non-purchasers. Teens who purchased both alcohol and marijuana experienced similar outcomes to those who purchased only marijuana, and also reported more frequent and higher quantity of drinking, greater alcohol-related consequences, time spent around teens who use other drugs, and prescription drug misuse. Longitudinally, purchasing alcohol and marijuana at baseline was associated with more frequent and higher quantity of drinking compared to non-purchasers at follow-up. Marijuana only purchasers had a greater likelihood of substance use disorders at follow-up compared to non-purchasers.

CONCLUSIONS

In an era where drinking is commonplace and attitudes towards marijuana use are becoming more tolerant, it is essential to evaluate how accessibility to AOD and subsequent purchasing behaviors affect youth consumption and intervene accordingly to prevent future consequences.

Are users' most recent drug purchases representative?

BACKGROUND

Various surveys now ask respondents to describe their most recent purchase of illicit drugs, as one mechanism through which market size can be estimated. This raises the question of whether issues surrounding the timing of survey administration might make a sample of most recent purchases differ from a random sample of all purchases. We investigate these issues through a series of questions which ask about the three most recent purchases, and about drug use.

METHODS

Data were drawn from 688 respondents in the Melbourne Injecting Drug User Cohort Study across the period 2008-2013 and 2782 respondents to the Washington Cannabis Consumption Study in 2013. Responses to questions about the most recent purchases were compared to larger subsets of all recent purchases.

RESULTS

For heroin, methamphetamine and cannabis no differences were found between the amount spent by participants on their most recent purchase and the average amount spent on three or more recent purchases. There were also no differences concerning the locations and types of deals, and the duration between consecutive cannabis purchases was the same for first and second most recent, and second and third most recent.

CONCLUSIONS

Asking about the most recent purchase appears to be an economical way to learn about purchases more generally, with little evidence of substantial variation between the most recent purchase and other recent purchases reported by participants. In spite of consistent findings across our two surveys, further replication of the work reported in this paper involving other populations of users is warranted.

Why Changes in Price Matter When Thinking About Marijuana Policy: A Review of the Literature on the Elasticity of Demand

Recent debates regarding liberalization of marijuana policies often rest on assumptions regarding the extent to which such policy changes would lead to a change in marijuana consumption and by whom. This paper reviews the economics literature assessing the responsiveness of consumption to changes in price and enforcement risk and explicitly considers how this responsiveness varies by different user groups. In doing so, it demonstrates how most of the research has examined responsiveness to prevalence of use, which is a composite of different user groups, rather than level of consumption among regular or heavy users, which represent the largest share of total quantities consumed. Thus, it is not possible to generate reliable estimates of the impact of liberalizing policies on either tax revenues or harms, as these outcomes are most directly influenced by the amounts consumed by regular or heavy users, not prevalence rates.

Can tobacco control endgame analysis learn anything from the US experience with illegal drugs?

The goals of tobacco control endgame strategies are specified in terms of the desired levels of tobacco use and/or tobacco related health consequences. Yet the strategies being considered may have other consequences beyond tobacco use prevalence, forms and related harms. Most of the proposed strategies threaten to create large black markets with potential attendant harms: corruption, high illegal earnings, violence and/or organised crime. Western societies of course have considerable experience with these problems in the context of prohibition of drugs such as cannabis, cocaine, heroin and methamphetamine. These experiences suggest that low prevalence has been achieved only by tough enforcement with damaging unintended consequences. Tobacco prohibition (total or partial) may not present the same trade-off but there is little basis for making a projection of the scale, form and harms of the attendant black markets. Nonetheless, these harms should not be ignored in analyses of the endgame proposals.

Statistics on cannabis users skew perceptions of cannabis use

Collecting information about the prevalence of cannabis use is necessary but not sufficient for understanding the size, dynamics, and outcomes associated with cannabis markets. This paper uses two data sets describing cannabis consumption in the United States and Europe to highlight (1) differences in inferences about sub-populations based on the measure used to quantify cannabis-related activity; (2) how different measures of cannabis-related activity can be used to more accurately describe trends in cannabis usage over time; and (3) the correlation between frequency of use in the past-month and average grams consumed per use-day.

KEY FINDINGS

focusing on days of use instead of prevalence shows substantially greater increases in U.S. cannabis use in recent years; however, the recent increase is mostly among adults, not youth. Relatively more rapid growth in use days also occurred among the college-educated and Hispanics. Further, data from a survey conducted in seven European countries show a strong positive correlation between frequency of use and quantity consumed per day of use, suggesting consumption is even more skewed toward the minority of heavy users than is suggested by days-of-use calculations.