Implications of marijuana purchase task based demand functions for optimal legal pricing of cannabis

Concurrent validity of the marijuana purchase task: a meta-analysis of trait-level cannabis demand and cannabis involvement

BACKGROUND AND AIMS

The Marijuana Purchase Task (MPT) is increasingly used to measure cannabis reinforcing value and has potential use for cannabis etiological and regulatory research. This meta-analysis sought to evaluate for the first time the MPT's concurrent validity in relation to cannabis involvement.

METHODS

Electronic databases and pre-print repositories were searched for MPT studies that examined the cross-sectional relationship between frequency and quantity of cannabis use, problems, dependence, and five MPT indicators: intensity (i.e. unrestricted consumption), Omax (i.e. maximum consumption), Pmax (i.e. price at which demand becomes elastic), breakpoint (i.e. first price at which consumption ceases), and elasticity (i.e. sensitivity to rising costs). Random effects meta-analyses of cross-sectional effect sizes were conducted, with Q tests for examining differences by cannabis variables, meta-regression to test quantitative moderators, and publication bias assessment. Moderators included sex, number of MPT prices, variable transformations, and year of publication. Populations included community and clinical samples.

RESULTS

The searches yielded 14 studies (n = 4077, median % females: 44.8%: weighted average age = 29.08 [SD = 6.82]), published between 2015 and 2022. Intensity, Omax , and elasticity showed the most robust concurrent validity (|r's| = 0.147-325, ps < 0.014) with the largest significant effect sizes for quantity (|r| intensity = 0.325) and cannabis dependence (|r| Omax  = 0.320, |r| intensity = 0.305, |r| elasticity = 0.303). Higher proportion of males was associated with increased estimates for elasticity-quantity and Pmax -problems. Higher number of MPT prices significantly altered magnitude of effects sizes for Pmax and problems, suggesting biased estimations if excessively low prices are considered. Methodological quality was generally good, and minimal evidence of publication bias was observed.

CONCLUSIONS

The marijuana purchase task presents adequate concurrent validity to measure cannabis demand, most robustly for intensity, Omax , and elasticity. Moderating effects by sex suggest potentially meaningful sex differences in the reinforcing value of cannabis.

Endometriosis and Cannabis Consumption During the COVID-19 Pandemic: An International Cross-Sectional Survey

Introduction: Endometriosis affects 1 in 10 women worldwide, with most experiencing difficulties achieving adequate symptom control. These difficulties have been compounded by the onset of the COVID-19 pandemic due to worldwide shifts in health care resource allocation. As cannabis is a relatively common form of self-management in endometriosis, this study aims to explore the impact of the COVID-19 pandemic on cannabis consumption in those with endometriosis. Methods: An anonymous, cross-sectional online international survey was developed and promoted by endometriosis advocacy/support organizations worldwide. Respondents needed to have a diagnosis of endometriosis and be aged between 18 and 55. Results: A total of 1634 responses were received from 46 different countries. The average age of respondents was 30, with a mean diagnosis age of 25. Eight hundred forty-six respondents (51%) reported consuming cannabis in the past 3 months, with 55% of these reporting use for symptom management only. One in five respondents (20%) reported having consumed cannabis previously, the most common reason for discontinuation (65%) was access difficulties during COVID. Those who had legal access were more likely to consume cannabis than those without (p<0.0001) and were more likely to disclose usage to health care professionals (p<0.0001). The most common reasons for consuming cannabis during COVID was increased stress/anxiety (59%) and lack of access to normal medical care (48%). Pre-pandemic, cannabis was mostly consumed at least once a day (61%) and in inhaled forms (51.6%). Consumption increased for most people (57%) during the pandemic. During the pandemic just under a quarter (23%) of respondents changed their mode of consumption, with a reduction in inhaled forms (39.5%) and an increase in consumption of edibles (40%) or oil (25.2%). Conclusions: Cannabis consumption, especially for symptom relief, was relatively common among those with endometriosis, with some people starting their consumption of cannabis due to health care restrictions that occurred due to the COVID-19 pandemic. Difficulties accessing cannabis and unpleasant/unwanted side effects were the most common reasons for lack of current cannabis consumption in those who had previously consumed it. Cannabis consumption may form an important part of endometriosis management especially when access to routine medical care is restricted.