What Have Been the Public Health Impacts of Cannabis Legalisation in the USA? A Review of Evidence on Adverse and Beneficial Effects

Avatar Intervention in Virtual Reality for Cannabis Use Disorder in Individuals With Severe Mental Disorders: Results From a 1-Year, Single-Arm Clinical Trial

Background

The dual diagnosis of cannabis use disorder (CUD) and severe mental disorder (SMD) results in clinically complex individuals. Cannabis use is known to have negative consequences on psychiatric symptoms, medication compliance, and disease prognosis. Moreover, the effectiveness of currently available psychotherapeutic treatments is limited in this population. In this context, our research team developed avatar intervention, an approach using virtual reality as a therapeutic tool to treat CUD in individuals with SMD.

Objective

This pilot clinical trial aimed to evaluate, until the 1-year follow-up, the efficacy of avatar intervention for CUD among 32 participants with a dual diagnosis of SMD and CUD.

Methods

Over the course of the 8 intervention sessions, participants were given the opportunity to enter a dialogue in virtual reality with an avatar representing a person with a significant role in their consumption, who was animated in real time by a therapist. The primary outcomes were the quantity of cannabis consumed and the frequency of use. Secondary outcomes included severity of problematic cannabis use, motivation for change, protective strategies for cannabis use, consequences of cannabis use, psychiatric symptoms, and quality of life. Changes in reported outcomes during the assessment periods before the intervention; postintervention; and 3, 6, and 12 months after the end of the intervention were assessed using a linear mixed-effects model.

Results

Significant reductions were observed in the quantity of cannabis consumed, and these were maintained until the 12-month follow-up visit (d=0.804; P<.001; confirmed by urine quantification). Frequency of cannabis use showed a small significant reduction at the 3-month follow-up (d=0.384; P=.03). Moreover, improvements were observed in the severity of CUD, cannabis-related negative consequences, the motivation to change cannabis use, and the strategies used to mitigate harms related to cannabis use. Finally, moderate benefits were observed for quality of life and psychiatric symptoms.

Conclusions

Overall, this unique intervention shows promising results that seem to be maintained up to 12 months after the end of the intervention. With the aim of overcoming the methodological limitations of a pilot study, a single-blind randomized controlled trial is currently underway to compare the avatar intervention for CUD with a conventional addiction intervention.

The Role of Savoring in Young Adult Cannabis Use and Associated Consequences: A Replication Study

Young adults exhibit high rates of cannabis use and are at heightened risk of experiencing negative cannabis-associated consequences. The purpose of the present study was to replicate and extend to prior work on savoring, the ability to experience positive experiences/emotions, and cannabis use frequency on cannabis-associated consequences. Young adults (18-25 years old, N = 122, 36.1% women) who reported weekly cannabis use completed self-report surveys. Savoring was significantly associated with cannabis use frequency (r = .28, p < .01) and cannabis-associated consequences (r = -.20, p < .05). Cannabis use frequency was significantly and negatively associated with cannabis-associated consequences (r = -.24, p < .01). However, the interaction between cannabis use frequency and savoring on cannabis-associated consequences was not significant (b = 0.0004, p = .91, 95% CI [-0.007, 0.008]). When the interaction was removed, neither cannabis use frequency (b = -0.14, p = .08, CI [-0.29, -0.02]) nor savoring (b = -0.05, p = .16, CI [-0.13, 0.02]) were associated with cannabis-associated consequences. Results did not replicate previous findings regarding the moderating role of savoring in the relationship between cannabis use frequency and cannabis-associated consequences. Future research may explore why findings did not replicate by using more fine-grained assessment methods and comprehensive measures of cannabis use.

Effects of Recreational Cannabis Legalization on Mental Health: Scoping Review

OBJECTIVE

Recreational cannabis legalization (RCL) is expanding rapidly. RCL's effects on mental health issues are of particular concern because cannabis use is more frequent among people receiving psychiatric care and is associated with several psychiatric disorders. The authors conducted a scoping review to examine the evidence and discern gaps in the literature concerning the effects of RCL on mental health and to assess the factors responsible for an observed heterogeneity in research results.

METHODS

This scoping literature review followed PRISMA guidelines. Five databases-MEDLINE, CINAHL, Embase, APA PsycInfo, and Web of Science-were searched for English- or French-language reports published between January 1, 2012, and April 30, 2023.

RESULTS

Twenty-eight studies from the United States and Canada were found. The studies were classified by category of the study's data (patients receiving psychiatric care [k=1], death records [k=4], emergency department or hospital records [k=10], and the general population [k=13]) and by the diagnosis (schizophrenia or psychoses, mood disorders, anxiety disorders and symptoms, suicide or suicidal ideation, or other mental health issues) examined. The review findings revealed a paucity of research and indicated mixed and largely inconclusive results of the studies examined. Research gaps were found in the examination of potential changes in cannabis use patterns among people receiving psychiatric care and in the availability of longitudinal studies.

CONCLUSIONS

Clinicians, researchers, and policy makers need to collaborate to address the research gaps and to develop evidence-based policies that reflect a thorough understanding of the effects associated with RCL.

Cannabis Users' and Non-Users' Differential Responses to Two Anti-Cannabis Campaigns

Even though multiple states have approved legal recreational use of cannabis, the expansion of recreational cannabis legalization has led to public health concerns in the United States. Young adults (18-25 years old) have the highest percentage of cannabis use disorder compared to all other age groups. The purpose of this study is to compare cognitive and emotional responses of young adults who use cannabis and non-users to two anti-cannabis media campaigns that employed different message strategies. In total, 50 people (25 people who use cannabis and 25 non-users) participated in the study-a 2 (cannabis use status: people who currently use cannabis/non-users) × 2 (Public Service Advertising [PSA] campaign: Don't be a Lab Rat-Informational/Stoner Sloth-Narrative) × 3 (message replication) experiment. Participants viewed six messages based on the combinations of each of the three message replications within two campaigns. Participants' facial emotional responses were recorded during message exposure. Self-report questions were asked after viewing each message. Self-report indices showed no differences between the two campaigns for participants who use cannabis and non-users. However, after controlling for individual differences, participants who use cannabis displayed more negative emotional responses to the Don't be a Lab Rat messages than to the Stoner Sloth messages. Conversely, cannabis users experienced more positive emotional responses to the Stoner Sloth messages than to the Don't be a Lab Rat messages. The study provides insights for message design in public health campaigns addressing cannabis use, suggesting that psychophysiological measures can be helpful in providing insights into responses not detected by traditional self-report measures.

Presentation, Management, and Child Protective Service Reporting of Children Who Test Positive for Cannabis in an Emergency Room Setting

OBJECTIVES

Rates of cannabis ingestion among young children are increasing. Small studies have evaluated symptomatology of these children. The literature lacks research regarding factors influencing medical management. Our goal was to 1) understand circumstances leading to exposure over time and 2) gain insight into factors that may influence emergency room management and Child Protective Services reporting over time.

METHODS

Retrospective cross-sectional study on children younger than 10 years with cannabis-positive urine drug screens in the emergency room setting. Single-factor analysis of variance and Fisher exact tests were used to assess for trends. Two-tailed t tests and Fisher exact tests were used to compare management of children presenting to the emergency room with chief complaint (CC) "ingestion" versus those without.

RESULTS

Of the 179 children, the mean age was 3.7 years and 48% were boys. We observed a significant increase over time in cannabis-positive children. The most common location of exposure was the primary residence (54%), with parents as the most frequent users (46%). In the emergency department, the most common CC was ingestion followed by altered mental status and fatigue. Children with an "ingestion" CC were managed with less testing than those with other CCs. They received fewer needle sticks (43% vs 91%), less imaging (5% vs 56% computed tomography heads), and fewer procedures (0% vs 8% lumbar punctures). Children with "ingestion" CC were less likely to be reported to Child Protective Services.

CONCLUSIONS

Pediatric cannabis exposures are increasing and have a wide array of clinical presentations that complicate emergency room management. Parental report of cannabis ingestion seems to impact and reduce potentially unnecessary testing.

Child Protection System Interactions for Children With Positive Urine Screens for Illicit Drugs

Importance

Young children are ingesting illicit drugs at increased rates, but it is unknown what the associated child protection system (CPS) responses are when a child tests positive.

Objective

To document the child protection system involvement and the characteristics of children who test positive for illicit substances.

Design, Setting, and Participants

This retrospective cross-sectional study linked medical discharge and child protection system administrative data. The setting was Rady Children's Hospital San Diego, a free-standing pediatric hospital in California. Participants included all emergency department and inpatient medical encounters involving children aged 12 years or younger with a positive urine drug test between 2016 and 2021. Statistical analysis was performed from February 2023 to January 2024.

Exposure

Drug type, including amphetamines, barbiturates, benzodiazepines, cannabis, cocaine, fentanyl, opiates, and phencyclidine.

Main Measures and Outcomes

CPS responses associated with the medical encounter including reports, substantiations, case openings, and out-of-home placements.

Results

A total of 511 emergency department and inpatient medical encounters involving children had a positive drug test (262 [51.3%] were female; 309 [60.5%] were age 6 years or younger; fewer than 10 [<3.0%] were American Indian or Alaska Native; 252 [49.3%] were Hispanic [any race], 20 [3.9%] were non-Hispanic Asian, 56 [11.0%] were non-Hispanic Black, 143 [28.0%] were non-Hispanic White, 36 [7.0%] had other or unknown race and ethnicity; 233 [43.6%] had a CPS report prior to the medical encounter). Following the positive screen, 244 (47.7%) were reported to child protection, and 61 (11.9%) were placed out-of-home within 30 days. Mean (SD) quarterly counts of encounters with positive drug tests doubled after the COVID-19 pandemic onset (32.9 [9.8]) compared with prior to the pandemic onset (16.5 [4.7]); for encounters positive for cannabis, mean (SD) quarterly counts were 3 times as high after the pandemic onset than prior (16.6 [4.7] vs 5.7 [2.9]). Encounters for children under age 1 were significantly more likely to have associated child protection reports (relative risk [RR], 2.91 [95% CI, 2.21-3.83]) and child protection case openings (RR, 1.71 [95% CI, 1.07-2.72]) than encounters involving older children.

Conclusions and Relevance

In this cross-sectional study of emergency department and inpatient medical encounters, less than half of children with positive urine drug screens were reported to CPS; out-of-home placements were uncommon. With increased encounters for positive drug tests, it is unclear what services these children and families are receiving.

Acute pediatric cannabis intoxication: A scoping review

Little is understood about the unintended consequences of cannabis liberalization on children. Subsequently, this scoping review aimed to map and identify evidence related to acute cannabis intoxication in children. We searched three medical literature databases from inception until October 2019. We identified 4644 information sources and included 158 which were mapped by topic area relating to 1) public health implications and considerations; 2) clinical management; and 3) experiences and information needs of HCPs and families. Public health implications were addressed by 129 (82%) and often reported an increased incidence of acute pediatric cannabis intoxications. Clinical information was reported in 116 (73%) and included information on signs and symptoms (n = 106, 92%), clinical management processes (n = 60, 52%), and treatment recommendations (n = 42, 36%). Few sources addressed the experiences or information needs of either HCPs (n = 5, <1%) treating children for acute cannabis intoxication or families (n = 1, <1%) seeking care. Increasing incidence of acute cannabis intoxications concurrent with liberalization of cannabis legislation is clear, however, evidence around clinical management is limited. Additionally, further research exploring HCPs and families experiences and information needs around cannabis intoxication is warranted.

Perceived Safety, Not Perceived Legality, Mediates the Relationship Between Cannabis Legalization and Drugged Driving

Cannabis legalization has rapidly spread throughout the United States and is associated with multiple public health outcomes, including driving under the influence of cannabis (DUIC). To improve understanding of the relationship between legalization and DUIC, we tested two potential mediators of this relationship: perceived safety and perceived legality of driving high. We analyzed data from 1,236 current (past 30-day) cannabis users who were recruited from states with recreational, medical only, or no legal cannabis between 2016 and 2017 using address-based and social media samples. Using a generalized linear model and adjusting for cannabis legalization, demographics, living in a state with a cannabis-specific drugged driving law, frequency of cannabis use, and weights, we found that perceived safety (risk ratio [RR] = 2.60, 95% CI [1.88, 3.58]), but not perceived legality (RR = 0.96, 95% CI [0.67, 1.37]), was significantly associated with DUIC. Perceived safety mediated the relationship between legalization and DUIC (Coeff: -0.12, 95% CI [-0.23, -0.01]). Models stratified by frequency of cannabis use yielded results consistent with those of pooled models except that, for frequent users, cannabis-specific driving laws were associated with a significantly lower risk of DUIC (RR = 0.64, 95% CI [0.44, 0.92]). Agencies developing cannabis-focused drugged driving educational campaigns should consider the potential role of perceived safety of driving high in DUIC campaigns.

The implementation and public health impacts of cannabis legalization in Canada: a systematic review

AIMS

We provide a narrative summary of research on changes in cannabis arrests, cannabis products and prices, cannabis use and cannabis-related harm since legalization.

METHODS

We systematically searched for research on the impacts of cannabis legalization in Canada in PubMed, Embase, Statistics Canada and government websites and Google Scholar, published between 2006 and 2021.

RESULTS

Cannabis legalization in Canada has been followed by substantial reductions in cannabis-related arrests and cannabis prices. It has also increased adults' access to a diverse range of cannabis products, including edibles and extracts. The prevalence of cannabis use among young adults has increased, but there have been no marked increases or decreases in use among high school students or changes in the prevalence of daily or near-daily use. Legalization has been associated with increased adult hospital attendances for psychiatric distress and vomiting, unintentional ingestion of edible cannabis products by children and hospitalizations for cannabis use disorders in adults. There is conflicting evidence on whether cannabis-impaired driving has increased since legalization. There is suggestive evidence that presentations to emergency departments with psychoses and cannabis use disorders may have increased since legalization.

CONCLUSIONS

Legalization of cannabis in Canada appears to have reduced cannabis arrests and increased access to a variety of more potent cannabis products at lower prices. Since 2019, recent cannabis use in Canada has modestly increased among adults but not among adolescents. There is evidence of increased acute adverse effects of cannabis among adults and children.

Population-based examination of substance use disorders and treatment use among US young adults in the National Survey on Drug Use and Health, 2011-2019

Background

Compared with adults of other age groups, young adults are more likely to have substance use disorders (SUDs) but less likely to receive treatment. Untreated SUDs can lead to lethal consequences, particularly deaths related to drug overdose.

Objectives

This study aimed to examine trends and sociodemographic differences in the prevalence and treatment use of SUDs among US young adults aged 18 to 25 in the National Survey on Drug Use and Health 2011-2019.

Methods

Bivariable logistic regression analyses were conducted to examine annual changes in the prevalence and treatment use of SUDs, and multivariable logistic regression was used to examine sociodemographic differences in SUD prevalence and treatment use in the pooled sample of young adults from 2011 to 2019.

Results

From 2011 to 2019, the overall SUD prevalence increased significantly from 5.4% to 6.2%. Cannabis use disorder was the most common SUD annually. Groups with lower prevalence of SUDs included females, young adults aged 22-25, and Hispanic, Black, and Asian participants. Across the survey years, the prevalence of treatment use fluctuated insignificantly between 10.9% and 16.9% among young adults with SUDs, and most young adults received SUD treatment in self-help groups and residential and outpatient rehabilitation facilities. Compared to White participants, treatment use was lower in Hispanic, Black, Asian participants, as well as young adults of two or more races. Young adults covered by Medicaid/CHIP were more likely to use treatment.

Conclusions

This study revealed an alarming level of unmet treatment need and significant disparities in treatment use among young adults with SUDs. To reduce barriers to treatment utilization, more coordinated efforts that leverage policy and structural changes alongside innovations to engage young adults with SUD care are needed.

Revisiting the effect of recreational marijuana on traffic fatalities

BACKGROUND

This study examines the effect of retail recreational marijuana legalization on traffic fatalities using the most current data available and recent advancements in difference-in-difference estimation methods proposed by Callaway and Sant'Anna, (2021).

METHOD

A modified difference-in-difference (CS-DID) is used to estimate the effect of recreational marijuana legalization on traffic fatalities reported in the Fatality Analysis Reporting System (FARS). Difference-in-difference regression models are run at the state-year level, using data from 2007 through 2020, and compared to estimates using traditional two-way-fixed-effects (TWFE) models.

RESULTS

Consistent with past studies, results from conventional TWFE suggest traffic fatalities increase at a rate of 1.2 per billion vehicle miles traveled (BVMT) after retail of recreational marijuana begins. However, using the CS-DID model, we find slightly larger average total treatment effects (∼2.2 fatalities per BVMT). Moreover, the size of the effect changes across time, where cohorts "treated" earlier have substantially higher increases than those who more recently legalized.

CONCLUSION

Traffic fatalities increase by 2.2 per billion miles driven after retail legalization, which may account for as many as 1400 traffic fatalities annually. States who legalized earlier experienced larger traffic fatality increases. TWFE methods are inadequate for policy evaluation and do not capture heterogeneous effects across time.

Recreational cannabis legalization alters associations among cannabis use, perception of risk, and cannabis use disorder treatment for adolescents and young adults

OBJECTIVE

Understanding how recreational cannabis legalization may impact cannabis use disorder (CUD) among adolescents and young adults is key to developing an appropriate public health response. This research investigates whether associations among adolescent and young adult perception of risk of harm from cannabis use, prevalence of past-month cannabis use, and rate of CUD treatment admissions changed following recreational cannabis legalization in the US, 2008-2019.

METHODS

Data from the NSDUH and TEDS-A datasets are employed in difference-in-differences models of the effect of recreational legalization on perception of risk, cannabis use prevalence, and CUD treatment admissions. Moderated models test whether associations among variables changed following recreational legalization.

RESULTS

Following recreational legalization: 1) adolescent and young adult past-month cannabis use prevalence increased; 2) among both adolescents and young adults, the association of lower perception of risk of harm with higher cannabis use prevalence was strengthened; 3) among adolescents, the association of higher cannabis use prevalence with higher CUD treatment admissions was suppressed; and 4) among young adults, an association of higher cannabis use prevalence with lower CUD treatment admissions emerged.

CONCLUSIONS

Recreational legalization is likely to increase cannabis use among adolescents and young adults who perceive cannabis as less harmful, while at the same time reduce rates of CUD treatment utilization. These trends portend an increase in unmet need for CUD treatment for age groups particularly vulnerable to the development and negative consequences of CUD.

The effects of the 4/20 cannabis holiday and adult-use cannabis legalization on medical cannabis sales and medical cannabis patient registration in Arizona

BACKGROUND

This study examined whether the 4/20 cannabis holiday was associated with increases in medical cannabis sales from licensed dispensaries in Arizona from 2018-2021, and whether adult-use cannabis legalization (the vote in November 2020 and retail sales in January 2021) was associated with declines in medical cannabis sales and in the number of registered medical patients.

METHODS

Data came from the Arizona Medical Marijuana Program monthly reports from January 2018-December 2021. The reports show daily sales from licensed medical cannabis dispensaries (i.e., the number of medical cannabis dispensary transactions and the amount of cannabis sold in pounds), which we averaged by week, and show the number of registered medical cannabis patients each month. Autoregressive integrated moving average models were used to test changes in these outcomes associated with the 4/20 cannabis holiday and with legalization of adult-use cannabis.

RESULTS

During the week of the 4/20 cannabis holiday, medical cannabis dispensary transactions abruptly increased by an average of 2,319.4 transactions each day (95% CI: 1636.1, 3002.7), and the amount of medical cannabis sold increased by an average of 120.3 pounds each day (95% CI: 99.3-141.3). During the first week of adult-use cannabis sales in late January 2021, medical cannabis dispensary transactions abruptly decreased by an average of 5,073 transactions each day (95% CI: -5,929.5, -4216.7), and the amount of medical cannabis sold decreased by an average of 119.1 pounds each day (95% CI: -144.2, -94.0). Moreover, medical cannabis sales continued to gradually decline each week after the start of adult-use retail sales, with declines in sales preceding declines in registered patients. By December 2021, slightly over a year after the vote to legalize adult-use cannabis, the actual number of registered medical cannabis patients fell short of the forecasted number, had adult-use not been legalized, by 36.5%. Moreover, the number of medical dispensary transactions and the amount of medical cannabis sold fell short of expectations, had adult-use cannabis not been legalized, by 58% and 53%, respectively.

CONCLUSIONS

Findings document the blurred boundary between medical and non-medical cannabis use and are consistent with the possibility that medical cannabis legalization contributes to increases in adult cannabis use and dependence.

A Systematic Review and Narrative Synthesis of the Evolution of Adolescent and Young Adult Cannabis Consumption Before and After Legalization

PURPOSE

To systematically review evidence assessing the evolution of cannabis consumption before and after the implementation of non-medical cannabis legislation.

METHODS

MEDLINE, PubMED, PsycINFO, Scopus, and Web of Science were systematically searched for studies that examined change in cannabis consumption before and after nonmedical cannabis legislation. Data were tabulated by study design, levels of consumption, and individual subgroups. Data were analyzed using a narrative synthesis approach, considering study quality.

RESULTS

32 studies were included (11 higher quality and 21 lower quality). 40% of higher quality evidence supported an increase in postlegalization consumption (55% did not report a change and 5% reported a decrease). The increase was most evident for young adults (42% of higher quality evidence) and in the consumption in the past month (37% of higher quality evidence). There was limited supporting evidence for new users having grown in response to legalization. Based on subgroup analysis, the increase in postlegalization consumption was higher among women and those who engage in binge-drinking.

CONCLUSIONS

Higher quality evidence suggests an increase in adolescent past-month consumption of cannabis following legalization in several geographical jurisdictions. Consumption evolution prelegalization and postlegalization differed by age group and for young women and for binge drinkers. Consumption evolution differences suggest a variety of strategies might be required in efforts to lower public health impacts of cannabis consumption following legalization.

Do alcohol and cannabis substitute or complement each other? Analysis from behavioral economics for formulating public policy on substance use in Colombia

After alcohol and tobacco, cannabis is the third most used substance among young Colombian adults, and many consume alcohol and cannabis concomitantly. However, academics have debated whether these substances substitute or complement each other among consumers. Understanding the relationship between the price and demand for psychoactive substances can clarify consumption patterns and help to develop strategies to reduce harmful consumption. This paper summarizes worldwide evidence of both complementary and substitution relationships and discusses the most probable relationship types in Colombia based on its substance use patterns and current regulations. Like other countries, Colombia is considering legalizing recreational cannabis use. However, there is a growing concern that legalization would increase the negative impacts of cannabis and increase alcohol use among the young adult population. The lack of Colombian empirical studies about the impacts of legal changes on the cannabis market makes it difficult to predict how such changes would affect demand and price elasticities.

Prevalence and self-reported reasons of cannabis use for medical purposes in USA and Canada

RATIONALE

There has been increasing attention on cannabis use for medical purposes, but there is currently a lack of data on its epidemiology.

OBJECTIVES

To examine the epidemiology of self-reported cannabis use for medical purposes by (1) estimating its prevalence, (2) comparing gender and age differences, and (3) investigating what reasons they were used to manage.

METHODS

Participants included 27,169 respondents (aged 16-65) who completed Wave 1 of The International Cannabis Policy Study (ICPS) conducted across Canada and the USA in 2018 via online surveys. Cannabis policy conditions were "US legal-recreational" (legal for both recreational and medical uses), "US legal-medical only", "US illegal", and "Canada-medical only".

RESULTS

The overall prevalence of self-reported ever cannabis use for medical purposes was 27%, with similar rates by sex and the highest prevalence in young adults. Prevalence was higher in US legal-recreational states (34%) than US illegal states (23%), US legal-medical only states (25%), and Canada (25%). The most common physical health reasons include use to manage pain (53%), sleep (46%), headaches/migraines (35%), appetite (22%), and nausea/vomiting (21%). For mental health reasons, the most common were for anxiety (52%), depression (40%), and PTSD/trauma (17%). There were 11% who reported using cannabis for managing other drug or alcohol use and 4% for psychosis.

CONCLUSIONS

A substantial proportion of the North American population self-reported cannabis use for medical purposes for a variety of medical reasons, including those living in jurisdictions without legal markets. Further research is needed to understand the safety and efficacy of these forms of medical cannabis use.

Self-reported perceived negative consequences of marijuana use among U.S. young adult users, 2008-2019

PURPOSE

This study estimated self-reported perceived negative marijuana use consequences among a national sample of U.S. young adults, examining consequence prevalence differences by use frequency, college attendance, living situation, employment, sex, and race/ethnicity; and use frequency/sociodemographic characteristic interactions.

METHODS

A subsample of 1,212 respondents from the 2004-2018 class cohorts of 12th grade students participating in the nationally-representative Monitoring the Future study was surveyed up to two times from modal ages 19 through 22 (in 2008-2019). Respondents self-reported negative consequences related to their own past 12-month marijuana use. Bivariate and multivariable models examined subgroup differences in consequence prevalence.

RESULTS

Approximately 60% of those using frequently (20+ use occasions in the past 30 days) and 35% of those using non-frequently reported negative consequences. Among all young adult marijuana users, 31.1% reported emotional/physical consequences, 12.9% performance/financial consequences, and 12.3% relational consequences. Use frequency was positively associated with consequence likelihood, excluding regret and unsafe driving. Among college students, frequent use was more strongly associated with any and performance/financial consequences. Controlling for use frequency, men reported more performance/financial consequences; relational consequences were higher among Hispanic (vs. White) respondents, and those living with parents, employed full-time, and not attending 4-year colleges.

CONCLUSION

Young adults using marijuana reported a wide range of negative use consequences; likelihood of most consequences increased with higher use frequency. Perceived consequences varied by college attendance, living situation, employment, sex, and race/ethnicity. Efforts to reduce negative marijuana consequences may be strengthened by recognizing and addressing the different types of negative consequences users perceive.

Legalization of recreational cannabis: Facilitators and barriers to switching from an illegal to a legal source

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Limiting surveillance, quantity limits, and preserving anonymity is a facilitator.

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Competitive pricing from the illicit market and heavy regulation are barriers.

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Loyalty to current illicit suppliers is a barrier to switching to a licit market.

Illicit markets persist in places where recreational cannabis has been legalized. This study aimed to identify perceived facilitators/barriers of switching from an illicit to a licit cannabis source. Using a cross-sectional qualitative approach, 529 students, from one New Zealand university, completed a survey investigating the facilitators/barriers to switching through two open-ended questions. Perceived facilitators for switching included: safety (63.1%); price (42.7%); legal, no risk of convictions (35.3%); increased accessibility (32.3%); product diversity (14.2%). Perceived barriers included: price (66.4%); judgement (36%); regulation (28.9%); loyalty to current supplier (27.2%); reduced accessibility (13.2%). The findings provide recommendations for policies aimed at tipping people in favor of a licit over an illicit source. Avoiding arrest/convictions, and easier access, were not primary facilitators for switching. Thus, providing a licit market might be insufficient in the absence of other competitive factors, such as communicating improved product safety. Competitive pricing and regulation (tetrahydrocannabinol strength/quantity limits) were also barriers. Given legal markets aimed at minimizing harm are constrained with competing in these areas, it is significant that our findings identified other barriers which could be overcome, including limiting surveillance and quantity limits and positioning stores to preserve anonymity. The findings also highlight that loyalty to current illicit suppliers will be a significant barrier.

Policy influence and the legalized cannabis industry: learnings from other addictive consumption industries

BACKGROUND AND AIM

New Zealand has recently legalized medicinal cannabis and has explored the possibility of legalizing large-scale recreational cannabis supply. In the process, concerns have emerged regarding whether corporations involved in the large-scale production and sale of legalized cannabis will invest in tactics of influence with policymakers and the public. This paper aimed to examine the various ways a legalized cannabis industry could seek to influence governments and the public in the New Zealand reform context.

METHOD

Based on the study of industry tactics with alcohol, tobacco and gambling, we applied a three-chain model of industry influence that breaks tactics into the 'public good', 'knowledge' and 'political' chains.

RESULTS

Exploratory analysis of the nascent cannabis industry's activity in New Zealand provided signs of industry influence strategies related to all three chains. The medicinal cannabis industry has associated the establishment of a legal cannabis sector with regional economic development and employment, supported lobbying for recreational law reform, funded NGOs involved in lobbying for law reform, established research partnerships with universities, invited ex-politicians on advisory boards, and participated in government public sector partnerships.

CONCLUSION

There is emerging evidence that the legal cannabis industry is using strategies to influence the regulatory environment in New Zealand.

Public health impacts to date of the legalisation of medical and recreational cannabis use in the USA

The legality of cannabis use has been changing in a number of jurisdictions around the world. In the U.S., it has been legalised for medicinal and/or recreational uses in 34 jurisdictions and counting. This study leverages the decades-long experience of legalisation in the U.S. to provide an overview of the associated changes in public attitudes, cannabis markets and adverse health effects. We found a broad-based warming of public attitudes toward legalisation, potentially influenced by the increasingly positive portrayal of cannabis in media and declines in cannabis risk perceptions. Potency of cannabis products increased significantly while prices fell sharply. Although adults were less responsive to price changes than adolescents, adults who use cannabis regularly were sensitive to prices, with an estimated 10% price reduction leading to about 2.5% increase in the rate of use. Overall, past-year cannabis use has increased in adults since 2002, and adults over 26 years old who resided in states with medicinal cannabis laws were more likely to have used cannabis in the past 30 days, to have used daily, and to have higher rates of cannabis use disorders than adults who resided in states without legalised medicinal cannabis. Traffic fatalities involving cannabis temporarily increased in some states post-legalisation, and there were more presentations to medical services related to chronic regular cannabis use. There is suggestive evidence that adverse health consequences have increased among people who use cannabis regularly since legalisation. More robust research is needed to determine whether these effects of legalisation are temporary or long-term.

Why did New Zealand's referendum to legalise recreational cannabis fail?

New Zealand recently held the world's first national referendum on cannabis legalisation involving a detailed bill to regulate retail sale and supply of cannabis for recreational (non-medical) adult use (i.e. the Cannabis Legalisation and Control Bill; CLCB). The referendum generated significant domestic debate and lobbying from both sides of the issue. The CLCB was narrowly defeated, with 48.4% voting to support versus 50.7% opposed. In this commentary, we discuss the referendum campaigns and other political and social factors that may have contributed to the result. Voting patterns appeared to largely follow traditional conservative-liberal, urban-rural and age divides. The referendum format created a public campaigning environment that encouraged persuasion and selective use of evidence rather than rational discussion of all the evidence and related knowledge gaps. The self-imposed neutrality of the centre left Labour Party and its popular leader may have been a decisive factor in the narrow defeat. It did not appear to be the case that anti-CLCB groups outspent the pro-CLCB movement in online promotional advertisements, and the leading digital media appeared largely neutral or mildly in favour of reform. The recent New Zealand experience illustrates the uncertainties of attempting to achieve cannabis law reform via a public referendum vote.

Do Cannabis Users Reduce Their THC Dosages When Using More Potent Cannabis Products? A Review

Background: Higher potency cannabis products are associated with higher risks of negative physical and psychological outcomes. The US cannabis industry has opposed any restrictions on THC levels, arguing that people titrate their THC doses when consuming higher potency products. Objective: To review research on the degree to which people who use cannabis for recreational purposes can and do titrate their THC doses. Method: A systematic search was conducted for studies published from 1973 to 2020. We included (1) experimental laboratory studies on dose titration of cannabis products that varied in THC content; (2) observational studies on the use of more potent products; and (3) surveys on whether cannabis users titrate when using more potent products. Results: In some experiments, there were inverse associations between the THC content and the amount smoked and smoking topography, while others indicated higher doses consumed and psychological and physiological effects observed. Findings of observational studies of regular cannabis users were more equivocal. In some surveys, cannabis users reported that they use less when using more potent products, but in other surveys, persons who used more potent cannabis had more adverse effects of use. Discussion: There is some evidence from experimental studies that people who use higher potency cannabis for recreational purposes can titrate their THC doses, but less evidence that regular cannabis users do in fact do so. We need much better experimental and epidemiological research to inform the design of regulatory policies to minimize harms from the use of high THC cannabis products.

How many more young Australians say that they would use cannabis if it were legal?

INTRODUCTION AND AIMS

The potential for increased cannabis use by young people after legalisation remains a key concern of opponents of legalisation. This study used survey data to estimate how many young Australians may be prepared to use cannabis if it became legally available.

DESIGN AND METHODS

The study included 3052 youths (adolescents aged 12-17 and young adults aged 18-25 years) in Australia who participated in the 2016 National Drug Strategy Household Survey. Incident cases were estimated by multiplying the prevalence and estimated population sizes from the Australian Bureau of Statistics.

RESULTS

It was estimated that 17% of adolescents would try (13%) or use (4%), and 32% of young adults would try (15%) or use (17%) cannabis if it were legal. Among those who reported an intention to try it, 85% of adolescents and 59% of young adults had never used cannabis. These translate to 199 000 and 238 000 potential initiators, respectively. Among those with an intention to use cannabis, 21% of adolescents and 3% of young adults had never used cannabis. These translate to 14 000 adolescents and 12 000 young adults who intended to use cannabis if it were legal.

DISCUSSION AND CONCLUSIONS

A substantial minority of young Australians say that they would use cannabis for the first time if it were legalised. A proportion of young people who have used cannabis also expressed an interest in increasing their use. Both would warrant special attention if cannabis were legalised.

Facing the option for the legalisation of cannabis use and supply in New Zealand: An overview of relevant evidence, concepts and considerations

ISSUES

Non-medical cannabis policies are changing, including towards legalisation-with-regulation frameworks. New Zealand will hold a public referendum on cannabis legalisation in 2020. We reviewed data on cannabis use and health/social harms; policy reform options; experiences with and outcomes of reforms elsewhere; and other relevant considerations towards informing policy choices in the upcoming referendum.

APPROACH

Relevant epidemiological, health, social, criminal justice and policy studies and data were identified and comprehensively reviewed.

KEY FINDINGS

Cannabis use is common (including in New Zealand) and associated with risks for health and social harms, mainly concentrated in young users; key harms are attributable to criminalisation. 'Decriminalisation' reforms have produced ambivalent results. Existing cannabis legalisation frameworks vary considerably in main parameters. Legalisation offers some distinct advantages, for example regulated use, products and user education, yet outcomes depend on essential regulation parameters, including commercialisation, and policy ecologies. While major changes in use are not observed, legalisation experiences are inconclusive to date, including mixed health and social outcomes, with select harms increasing and resilient illegal markets. It is unclear whether legalisation reduces cannabis exposure or social harms (e.g. from enforcement) for youth.

IMPLICATIONS/CONCLUSIONS

No conclusive overall evidence on the outcomes of legalisation elsewhere exists, nor is evidence easily transferable to other settings. Legalisation offers direct social justice benefits for adults, yet overall public health impacts are uncertain. Legalisation may not categorically improve health or social outcomes for youth. Legalisation remains a well-intended, while experimental policy option towards more measured and sensible cannabis control and overall greater policy coherence, requiring close monitoring and possible adjustments depending on setting-specific outcomes.