Validation of self-reported cannabis dose and potency: an ecological study

Typical Hits, Grams, or Joints: Evaluating Cannabis Survey Measurement Strategies for Quantifying Consumption

Aim: Standardized survey measures that capture diverse cannabis consumption patterns are needed to inform public health and policy. Our team is developing a flexible, personalized, low-burden survey item inventory to measure cannabis use patterns and estimate milligrams of THC (mgTHC) consumption in large samples. This study aimed to identify measurement gaps and analysis implications associated with an initial pool of candidate items that assessed use of cannabis flower and concentrate products (smoked and/or vaporized). Methods: Adult cannabis consumers (n=4247) completed an online survey assessing cannabis use frequency, quantity, product types, product potencies (%THC), and methods of administration. Participants chose to report their consumption quantities using one of three units: "hits per day," "grams per week," or "joints per week." Respondents also indicated whether their past 7-day consumption pattern represented their typical pattern. Results: Eighty-one percent had used cannabis daily in the past week. Thirty-two percent, 53%, and 15% chose to report flower and concentrate consumption quantity in hits, grams, and joints, respectively. Approximately 80-90% of responses for the number of hits, grams, and joints consumed were less than the maximum response option-suggesting that response options captured the full range of potential cannabis consumption behaviors. Those who chose grams or joints units were generally more likely to endorse higher risk cannabis use (e.g., morning use, high %THC products) in the past week than those who chose the hits unit (adjusted Odds Ratio range: 1.2-3.9). Among those who reported that the past week represented their typical behavior (83%), past 30-day and past 7-day frequencies were highly correlated (Spearman's Rho=0.77)-supporting the feasibility of using lower burden "typical week" items to extrapolate patterns beyond a 1-week time frame. Conclusion: Results from this online convenience sample of frequent cannabis consumers suggest that the current items yield coherent and expected response patterns. Although additional testing is required, a standardized, flexible survey instrument for large-scale assessment of cannabis patterns and calculation of mgTHC seems within reach.

Estimating THC Consumption from Smoked and Vaped Cannabis Products in an Online Survey of Adults Who Use Cannabis

Introduction: Quantification of consumption patterns of the primary psychoactive compounds in cannabis, which cause euphoria or intoxication, is sorely needed to identify potential risks and benefits of use and to provide meaningful safety information to the public. The diversity of products available, multiple methods of administration, and lack of labeling of products have made such quantification challenging. Our group is developing a survey instrument for estimating the quantity of delta 9-tetrahydrocannabinol (THC) consumed in population samples, which is flexible and incorporates individualized reports of patterns of consumption. This study provides an illustration of a procedure for translating self-reported consumption into milligrams of THC (mgTHC), which may serve as a working model for future quantification efforts. Methods: Social media advertising was leveraged to enroll 5627 adults who use cannabis into an online, anonymous survey study. Only those who used cannabis in the past 7 days, used flower or concentrate products, and who chose to report their quantity of use in hits per day or grams per week (n=3211) were included in this report. Formulas were used to estimate mgTHC used per day, in hits per day or grams per week; potency (%THC); constants for estimating the amount of material consumed for each hit; and a method of administration efficiency constant to account for THC loss due to the administration method. Results: The estimate for mgTHC used per day was M=92.8 mg/day (SD=97.2 mg; 1st-3rd quartile range=25-132 mg). The estimated quantity of use was much lower for those reporting in hits (M=43.7 mg, SD=43.8) than for those reporting in grams (M=115.1 mg, SD=107.0). The estimated rate of binge use in the past week, arbitrarily defined as more than 50 mgTHC within any one daily time quadrant, was 6.8%, which increased to 29.3% if 25 mgTHC was used. Conclusions: The approach illustrated in this study goes beyond existing cannabis measures by asking participants to provide highly detailed estimates of their past 7-day use patterns and then applying a logical formula to translate this information into mgTHC. This initial procedure has limitations and lacks generalization; however, we hope this demonstration stimulates testing of similar approaches and relevant laboratory experiments that will enhance the validity of cannabis consumption estimation procedures.

Daily diary study of associations between alcohol, cannabis, co-use and sleep quality in individuals with intentions to use cannabis to cope with anxiety

INTRODUCTION

Sleep problems and anxiety conditions are common comorbidities and may be influenced by cannabis and alcohol use. This study examined daily within-person variation in subjective sleep quality among individuals with anxiety symptoms after cannabis or alcohol were used alone, and after co-use.

METHODS

A total of 347 individuals with intentions to use cannabis to cope with anxiety reported their cannabis and alcohol use in the previous 24 h and their previous nights' sleep quality for 30 consecutive days. Mixed-effects models examined whether the within-person daily variation in use of cannabis and alcohol (alone and co-use) was associated with subjective sleep quality. Models also examined whether daily cannabis and alcohol use associations with sleep were moderated by frequency of cannabis, alcohol and co-use during the study period.

RESULTS

Compared to non-use, participants reported better sleep after cannabis-use-only and after co-use, but not after alcohol-use-only. People who more frequently use alcohol and cannabis reported sleeping better after cannabis-use-only days compared to those who use cannabis and alcohol less frequently.

DISCUSSION AND CONCLUSIONS

The study's utilisation of naturalistic data among individuals with anxiety symptoms replicated previously reported experimental findings among individuals without sleep and anxiety problems that overall, cannabis is associated with higher subjective sleep quality. The results expand upon other research to suggest that more frequent use of alcohol and cannabis may moderate daily associations of cannabis use and sleep, potentially through pharmacokinetics and cross-sensitisation.

How much cannabis is used in a joint in Australia? An experimental investigation into use by potency and frequency

INTRODUCTION

Cannabis use is highly prevalent in Australia, yet current survey metrics measure tetrahydrocannabinol (THC) exposure with limited accuracy. Often survey items measure cannabis quantity by assuming specific modes of use (i.e., 'how many joints do you use?'), which fail to capture variations in cannabis use and the diverse modes of use (e.g., joints, cones, spliffs). This study investigated how much cannabis is used in these modes of administration in an Australian sample.

METHODS

Participants (N = 31, Mage  = 25.77; 51% university students) completed the Roll a Joint Paradigm in which they rolled joints, spliffs and packed cones as they would typically, using oregano as 'cannabis.' Participants then prepared each again but with cannabis of higher or lower potency.

RESULTS

The amount of cannabis used across different modes of administration was variable: joints (range 0.10-1.25 g), spliffs (range 0.12-1.21 g) and cones (range 0.03-0.41 g). Participants who used cannabis daily rolled three times the amount of cannabis into a joint.

DISCUSSION AND CONCLUSIONS

The amount of cannabis used in common modes of administration may be highly variable. Daily use may be associated using larger quantities of cannabis. Titration attempts based on potency were not proportional or consistent across modes of administration. The results indicate people may adjust the quantity of cannabis based on perceived potency, however, not proportional to THC concentration. Inconsistency in the amount of cannabis used based on potency and within different modes of administration may represent a problem for self-report metrics which ask participants to report cannabis use in joints.

Development of Mobile Contingency Management for Cannabis Use Reduction

Many interventions for cannabis use disorder (CUD) are associated with decreases in frequency and quantity of use but fail to increase overall rates of sustained abstinence. It is currently unknown whether reductions in use (in the absence of sustained abstinence) result in clinically significant improvements in functioning. The objective of this study was to refine a mobile contingency management approach to reduce cannabis use to ultimately evaluate whether reductions in frequency and quantity of cannabis are related to improvements in functional and mental health status. Three cohorts of participants (n = 18 total, n = 10 women) were enrolled and completed 2 weeks of ecological momentary assessment (EMA) during a baseline ad lib cannabis use period, followed by a 6-week reduction period. Participants completed EMA assessments multiple times per day and were prompted to provide videotaped saliva cannabis testing 2-3 times daily. Data from participants who were at least 80% adherent to all EMA prompts were analyzed (13 out of 18). During the ad lib phase, participants were using cannabis on 94% of the days and reported using a mean of 1.42 grams daily. The intervention was a mobile application that participants used to record cannabis use by saliva tests to bioverify abstinence and participants completed electronic diaries to report their grams used. During the 6-week intervention phase, participants reported reducing their use days to 47% of the days with a reported mean of .61 grams daily. In the last cohort, at least 50% of the heavy users were able to reduce their cannabis use by at least 50%. The effect of cannabis reduction (versus abstinence) is largely unknown. Observations suggest that it is possible to develop a mobile intervention to reduce cannabis use among heavy users, and this paradigm can be utilized in future work to evaluate whether reductions in cannabis use among heavy users will result in improvements in functional and mental health status.

A longitudinal study of cannabis use and risk for cognitive and functional decline among older adults with HIV

Cannabis use is rapidly increasing among older adults in the United States, in part to treat symptoms of common health conditions (e.g., chronic pain, sleep problems). Longitudinal studies of cannabis use and cognitive decline in aging populations living with chronic disease are lacking. We examined different levels of cannabis use and cognitive and everyday function over time among 297 older adults with HIV (ages 50-84 at baseline). Participants were classified based on average cannabis use: frequent (> weekly) (n = 23), occasional (≤ weekly) (n = 83), and non-cannabis users (n=191) and were followed longitudinally for up to 10 years (average years of follow-up = 3.9). Multi-level models examined the effects of average and recent cannabis use on global cognition, global cognitive decline, and functional independence. Occasional cannabis users showed better global cognitive performance overall compared to non-cannabis users. Rates of cognitive decline and functional problems did not vary by average cannabis use. Recent cannabis use was linked to worse cognition at study visits when participants had THC+ urine toxicology-this short-term decrement in cognition was driven by worse memory and did not extend to reports of functional declines. Occasional (≤ weekly) cannabis use was associated with better global cognition over time in older adults with HIV, a group vulnerable to chronic inflammation and cognitive impairment. Recent THC exposure may have a temporary adverse impact on memory. To inform safe and efficacious medical cannabis use, the effects of specific cannabinoid doses on cognition and biological mechanisms must be investigated in older adults.

Measuring cannabis quantities in online surveys: A rapid review and proposals for ways forward

OBJECTIVES

Cannabis use quantities are relevant for determining cannabis-related harms. This research aims to provide an overview of the available methods to assess quantities through self-report.

METHODS

A rapid review of various strategies to collect information on cannabis use quantities through self-report. Two independent literature searches resulted in n = 38 studies included for review.

RESULTS

A total of n = 14 studies employed methods for collecting cannabis use quantities that are not suitable for online surveys (e.g., rolling a fake joint). Of the remaining n = 24 studies with items that are suitable for online surveys, the quantity assessment was performed in three different ways. The data collection was either carried out by asking (a) for the total number of joints (i.e., crude joint method), (b) for the total weight (i.e., crude weight method), or (c) for specific products separately, for example, for the amount of flower and resin (i.e., product-specific method). In only n = 8 studies, cannabis use quantities were ascertained by providing visual aids (e.g., illustration of various amounts of flower).

CONCLUSIONS

The crude joint method and the product-specific method are the two most promising methods to collect information on cannabis use quantities. Using visual aids may potentially improve the accuracy of those methods.

Cannabis use breaks in young adults: The highs and lows of tolerance breaks

BACKGROUND/PURPOSE

Cannabis tolerance breaks, or T-breaks, are believed to benefit persons who use cannabis (PUCs) by decreasing tolerance levels to cannabis. However, no prior research, to our knowledge, has compared the effects of T-breaks and other use breaks on cannabis use patterns and outcomes. The current study examined whether the occurrence of cannabis use breaks (tolerance and other use breaks), or the duration of these breaks, is associated with changes in hazardous cannabis use (CUDIT-R), CUD severity, cannabis use frequency, and withdrawal symptoms over a 6-month follow-up.

METHODS

Young adults, who recreationally use cannabis, (N=170, 55.9% female, Mean age=21 yo) completed baseline and on-time 6-month assessments of hazardous cannabis use (CUDIT-R), CUD severity, cannabis use frequency, and withdrawal symptoms. The occurrence of cannabis use breaks and the duration of these breaks during the intervening period was assessed at 6 months.

RESULTS

Taking a T-break was associated with an increase in hazardous cannabis use and CUD severity at 6 months. When considering cannabis use breaks for other reasons, a longer break was associated with a significant decrease in hazardous cannabis use (CUDIT-R), CUD severity, and cannabis use frequency at 6 months.

CONCLUSION

Findings from our study suggest recreational PUCs who take a T-break may be at greater risk for problematic cannabis use. In addition, taking a longer cannabis use break for other reasons may have beneficial effects on cannabis-related outcomes. The ability to abstain from cannabis for other reasons may be protective while individuals who take T-breaks may be important targets for intervention and prevention.

The acute effects of cannabis with and without cannabidiol in adults and adolescents: A randomised, double-blind, placebo-controlled, crossover experiment

BACKGROUND AND AIMS

Long-term harms of cannabis may be exacerbated in adolescence, but little is known about the acute effects of cannabis in adolescents. We aimed to (i) compare the acute effects of cannabis in adolescent and adult cannabis users and (ii) determine if cannabidiol (CBD) acutely modulates the effects of delta-9-tetrahydocannabinol (THC).

DESIGN

Randomised, double-blind, placebo-controlled, crossover experiment. The experiment was registered on ClinicalTrials.gov (NCT04851392).

SETTING

Laboratory in London, United Kingdom.

PARTICIPANTS

Twenty-four adolescents (12 women, 16- to 17-year-olds) and 24 adults (12 women, 26- to 29-year-olds) who used cannabis 0.5-3 days/week and were matched on cannabis use frequency (mean = 1.5 days/week).

INTERVENTION

We administered three weight-adjusted vaporised cannabis flower preparations: 'THC' (8 mg THC for 75 kg person); 'THC + CBD' (8 mg THC and 24 mg CBD for 75 kg person); and 'PLA' (matched placebo).

MEASUREMENTS

Primary outcomes were (i) subjective 'feel drug effect'; (ii) verbal episodic memory (delayed prose recall); and (iii) psychotomimetic effect (Psychotomimetic States Inventory).

FINDINGS

Compared with 'PLA', 'THC' and 'THC + CBD' significantly (P < 0.001) increased 'feel drug effect' (mean difference [MD] = 6.3, 95% CI = 5.3-7.2; MD = 6.8, 95% CI = 6.0-7.7), impaired verbal episodic memory (MD = -2.7, 95% CI = -4.1 to -1.4; MD = -2.9, 95% CI = -4.1 to -1.7) and increased psychotomimetic effects (MD = 7.8, 95% CI = 2.8-12.7; MD = 10.8, 95% CI = 6.2-15.4). There was no evidence that adolescents differed from adults in their responses to cannabis (interaction P ≥ 0.4). Bayesian analyses supported equivalent effects of cannabis in adolescents and adults (Bayes factor [BF01 ] >3). There was no evidence that CBD significantly modulated the acute effects of THC.

CONCLUSIONS

Adolescent cannabis users are neither more resilient nor more vulnerable than adult cannabis users to the acute psychotomimetic, verbal memory-impairing or subjective effects of cannabis. Furthermore, in adolescents and adults, vaporised cannabidiol does not mitigate the acute harms caused by delta-9-tetrahydocannabinol.

Differentiating people who use cannabis heavily through latent class analysis

BACKGROUND

People who use cannabis daily or near-daily vary considerably in their daily dosage and use frequency, impacting both experienced effects and adverse consequences. This study identified heavy cannabis user groups according to consumption patterns and factors associated with class membership.

METHODS

We conducted a cross-sectional study of 380 Spanish residents (61.8% male; average age = 30.3 years) who had used cannabis ≥ 3 days/week throughout the past year. Participants were recruited through chain referral and cannabis social clubs. We applied latent class analysis (LCA) to cluster participants according to use intensity. LCA indicators included frequency of weekly cannabis use, joints smoked each day, cannabis dosage, and if cannabis was consumed throughout the day or only at specific times. Associations between class membership and socio-demographics, use patterns, motives, supply sources, adverse outcomes, and use of other substances were measured using ANOVA and chi-squared tests. Multinomial regression identified the factors associated with latent class membership.

RESULTS

Three latent classes (moderately heavy: 21.8%, heavy: 68.2%, very heavy: 10%) had average weekly cannabis intakes of 2.4, 5.5, and 18.3 g, respectively. Very heavy users were older ([Formula: see text]=17.77, p < 0.01), less educated [Formula: see text]=36.80, p < 0.001), and had used cannabis for longer (F = 4.62, p = 0.01). CAST scores (F = 26.51, p < 0.001) increased across the classes. The prevalence of past-month alcohol use was lower among the heaviest users ([Formula: see text]=5.95, p = 0.05). Cannabis was usually obtained from a club by very heavy users ([Formula: see text]=20.95, p < 0.001).

CONCLUSIONS

People who use cannabis heavily present three groups according to frequency and quantity of cannabis consumption. Use intensity is associated with increased cannabis-related problems. Differences among heavy users must be considered in harm reduction interventions in cannabis clubs and indicated prevention.

Induced negative affect's impact on self-reported cannabis use, expectancies, and problems

Substance use disorders and affective disturbances often covary. Even momentary experiences of negative affect (NA) appear linked with substance use. While strong evidence of these relations exists, NA might bias endorsements of substance use due to hindered recall and reporting processes. This hypothesis warrants further research, as accurate assessment of substance-related variables is crucial in both research and treatment settings. The present study examined the influence of NA on reporting of cannabis variables using an affect-induction paradigm. Over 700 individuals recruited from Amazon's MTurk participated. After reporting demographics and baseline affect, participants were randomly assigned to either a NA induction or control condition. Follow-up measures assessed post-induction affect and cannabis-related variables. Results revealed that the NA induction task significantly increased NA and decreased positive affect relative to the control condition. Participants assigned to the NA induction reported greater negative cannabis expectancies and more cannabis problems, even after controlling for age and educational attainment. Cannabis use and cannabis problems appeared positively related. Future research should continue to assess for the influence of NA in reporting of cannabis variables. Should subsequent work find differences in reporting of substance use that appear to covary with negative affect, clinicians and researchers alike should be mindful of the implications of potentially biased reporting on assessment, intervention, and research outcomes.

Feasibility of an intensive interprofessional lifestyle medicine program for patients with musculoskeletal conditions in the setting of lifestyle-related chronic disease

BACKGROUND

Lifestyle factors are associated with musculoskeletal pain and metabolic chronic diseases. To date, intensive lifestyle medicine programs have predominantly targeted metabolic rather than musculoskeletal conditions.

OBJECTIVE

To assess the feasibility of an intensive interprofessional lifestyle medicine program for patients with musculoskeletal conditions.

DESIGN

Prospective observational feasibility study.

SETTING

Tertiary academic medical center.

PATIENTS

Adults diagnosed with musculoskeletal condition(s) and lifestyle-related chronic disease(s) who previously completed standard-of-care musculoskeletal treatments, enrolled from 2018 to 2020.

INTERVENTIONS

Patients enrolled in an intensive interprofessional lifestyle medicine program led by a physiatrist, with options to interface with an acupuncturist, dietician, massage therapist, psychologist, physical therapist, and smoking cessation specialist. The physiatrist engaged in shared decision making with patients to establish program goals related to function, overall health, and required lifestyle changes. Bimonthly interprofessional team conferences facilitated communication between treatment team and patients.

MAIN OUTCOME MEASURES

Feasibility was measured by patient participation and goal attainment. Secondary outcomes included changes from program enrollment to discharge in patient anthropometric, metabolic lab, sleep apnea risk, and Patient-Reported Outcomes Measurement Information System (PROMIS) function, pain, and behavioral health measures.

RESULTS

Twenty-six patients enrolled in the program (18 [69%] female, mean age 59 [SD 14.5] years, baseline hemoglobin A1c 6.0% [0.8%], high-sensitivity C-reactive protein 7.7 [12.1] mg/dL, 25-hydroxy vitamin D 32.0 [14.2] ng/mL). Of 21 (81%) patients who completed the program, 13/21 (62%) met their goal. On average, program completers presented for 26.2 (10.6) total visits over 191 (88) days. By discharge, program completers achieved clinically meaningful improvement in PROMIS Anxiety (mean difference -3.5 points, 95% confidence interval [-6.5 to 0.5], p = .035), whereas noncompleters did not (p > .05).

CONCLUSIONS

An intensive interprofessional lifestyle medicine program for patients with musculoskeletal conditions is feasible. With training in lifestyle intervention, physiatrists are well suited to lead interprofessional teams aimed at assisting patients in making lifestyle changes to achieve personalized function- and health-related goals.

Posttraumatic stress disorder, sleep and medical cannabis treatment: A daily diary study

Despite increasing use of Medical Cannabis (MC) among posttraumatic stress disorder (PTSD) patients, research is lacking on how MC treatment relates to PTSD symptomatology, in particular sleep disturbances. This study examines the time gap between MC use and sleep onset and its association with (1) number of awakenings throughout the night, (2) early awakenings, (3) nightmares. Each morning over a two week period, 77 licensed MC patients suffering from PTSD reported on the timing of previous night MC use and sleep disturbances. Within-person analyses found that shorter time gaps between previous night MC use and sleep start time was associated with lower likelihood of experiencing nightmares throughout the night, but it was not associated with nightly awakenings or waking up too early. Between-person analyses showed that individuals who used MC products with higher CBD concentrations reported fewer early awakenings. These preliminary results indicate that future research should test causal relations between MC use and sleep problems in PTSD patients. Future research is warranted in order to explore causal relationships between MC use, nightmares and insomnia in PTSD patients.

Association of cannabis potency with mental ill health and addiction: a systematic review

Cannabis potency, defined as the concentration of Δ⁹-tetrahydrocannabinol (THC), has increased internationally, which could increase the risk of adverse health outcomes for cannabis users. We present, to our knowledge, the first systematic review of the association of cannabis potency with mental health and addiction (PROSPERO, CRD42021226447). We searched Embase, PsycINFO, and MEDLINE (from database inception to Jan 14, 2021). Included studies were observational studies of human participants comparing the association of high-potency cannabis (products with a higher concentration of THC) and low-potency cannabis (products with a lower concentration of THC), as defined by the studies included, with depression, anxiety, psychosis, or cannabis use disorder (CUD). Of 4171 articles screened, 20 met the eligibility criteria: eight studies focused on psychosis, eight on anxiety, seven on depression, and six on CUD. Overall, use of higher potency cannabis, relative to lower potency cannabis, was associated with an increased risk of psychosis and CUD. Evidence varied for depression and anxiety. The association of cannabis potency with CUD and psychosis highlights its relevance in health-care settings, and for public health guidelines and policies on cannabis sales. Standardisation of exposure measures and longitudinal designs are needed to strengthen the evidence of this association.

Cannabis use as a predictor and outcome of positive and negative affect in college students: An ecological momentary assessment study

BACKGROUND

Reinforcement models identify negative affect (NA) and positive affect (PA) to be important momentary determinants and outcomes of cannabis use. Sensitization and allostatic models further suggest that these mood-cannabis associations are stronger among individuals with more cannabis-related problems. Despite this theoretical background and the fact that cannabis is commonly used for its mood-enhancing effects among college students, surprisingly, little is known about the momentary associations between mood and cannabis use in this population.

AIMS

To examine the associations between (a) momentary within-person variations in NA (worried, stressed, nervous) and PA (happy, enthusiastic, proud, excited) and intention to use cannabis within the next hour, (b) the within-person variations in time elapsed since last cannabis use, amount used and momentary NA and PA, and (c) to test whether cannabis-related problems moderate the stated associations.

METHOD

Eighty, more-than-weekly, cannabis using students at the University of Amsterdam reported on cannabis use, NA and PA three times daily for 14 consecutive days. Mixed-effects models were performed to analyze the dataset.

RESULTS

Within-persons, relatively high PA and low NA were associated with a higher likelihood of intending to use cannabis. Within-persons, more recent and greater amounts of cannabis use were associated with relatively high PA. More recent cannabis use was associated with relatively low NA. Cannabis-related problems did not moderate the associations.

CONCLUSIONS

While recent cannabis use related to higher PA and lower NA, high PA but low NA preceded use, supporting positive reinforcement rather than negative reinforcement in this college sample of regular cannabis users.

Analytical Techniques for Phytocannabinoid Profiling of Cannabis and Cannabis-Based Products-A Comprehensive Review

Cannabis is gaining increasing attention due to the high pharmacological potential and updated legislation authorizing multiple uses. The development of time- and cost-efficient analytical methods is of crucial importance for phytocannabinoid profiling. This review aims to capture the versatility of analytical methods for phytocannabinoid profiling of cannabis and cannabis-based products in the past four decades (1980–2021). The thorough overview of more than 220 scientific papers reporting different analytical techniques for phytocannabinoid profiling points out their respective advantages and drawbacks in terms of their complexity, duration, selectivity, sensitivity and robustness for their specific application, along with the most widely used sample preparation strategies. In particular, chromatographic and spectroscopic methods, are presented and discussed. Acquired knowledge of phytocannabinoid profile became extremely relevant and further enhanced chemotaxonomic classification, cultivation set-ups examination, association of medical and adverse health effects with potency and/or interplay of certain phytocannabinoids and other active constituents, quality control (QC), and stability studies, as well as development and harmonization of global quality standards. Further improvement in phytocannabinoid profiling should be focused on untargeted analysis using orthogonal analytical methods, which, joined with cheminformatics approaches for compound identification and MSLs, would lead to the identification of a multitude of new phytocannabinoids.

Identifying Subgroups of Cannabis Users Based on Help-Seeking Preferences: A Latent Class Analysis

BACKGROUND

The majority of people with cannabis use disorder do not seek treatment. If we were able to gain more insight into different subgroups of cannabis users based on help-seeking preferences, we could use this information to inform the development and promotion of interventions targeted at specific subgroups of cannabis users, to ultimately narrow the treatment gap.

METHODS

An online survey was conducted among 1,015 Dutch frequent cannabis users (18-72 years) to assess their cannabis use, help-seeking preferences, psychopathology, and psychological distress. Latent class analysis was used to identify classes of cannabis users based on their help-seeking preferences. Differences between the identified classes in terms of sociodemographics, cannabis use, and psychopathology were examined.

RESULTS

We identified four classes with distinct preferences for support. Class 1 ("no support/only social," n = 548) had a low probability of finding any form of support appealing other than social support. Class 2 ("online help," n = 170) had relatively high probabilities of finding online help appealing. Class 3 ("GP/outpatient," n = 208) had a relatively high probability of finding support from the general practitioner and outpatient substance use disorder treatment appealing. Class 4 ("all sources," n = 89) had moderate to high probabilities for all sources of support. In terms of sociodemographics, differences between the classes were found with regard to gender and level of education. The classes were fairly similar with regard to cannabis use, only the "online help" class scored significantly lower on both cannabis use frequency and quantity compared to most of the other classes. In terms of psychopathology, the "GP/outpatient" class and the "all sources" class experienced more cannabis use-related problems and were more likely to report multiple past quit attempts than the "online help" class and the "no support/only social" class.

CONCLUSIONS

Our study shows that there is a lot of inter-individual variation in how appealing various forms of help are to cannabis users. Our findings emphasize the importance of promoting a variety of treatment modalities for cannabis users, including real-life and digital options, and indicate what might appeal to whom.

Cannabis and Alcohol Use and Their Associations with Sleep: A Daily Diary Investigation of Single-Use and Co-Use in College Students

Introduction: Sleep continuity problems are widespread among college students and may be influenced by single-use and co-use of alcohol and cannabis. We examined the within-person associations of alcohol and cannabis use with subsequent sleep experiences in the everyday life of college students. Materials and Methods: A sample of 80 college students reported prior-night alcohol and cannabis use and sleep experiences for 14 consecutive days. Mixed-effects models examined the within-person relationships between alcohol and cannabis use (single- and co-use) and subsequent (1) sleep-onset latency, (2) total sleep time, (3) number of awakenings, and (4) early awakenings that night. Results: Compared to no-use evenings, alcohol and cannabis, used separately or together (co-use), were associated with shorter sleep-onset latency and longer total sleep time. Students reported more nightly awakenings after alcohol-only use compared to no-use and after co-use, and they reported fewer early awakenings after no-use and co-use. Conclusions: In line with previous experimental findings, we found that alcohol and cannabis use in the everyday life of college students were associated with sleep-inducing effects, and that alcohol use was associated with disturbed sleep continuity. The results suggest that cannabis may curb alcohol's detrimental effect on the number of awakenings and may reduce the incidence of early awakenings. Yet, due to lack of control for potentially important confounders (e.g., quantity of cannabis/alcohol consumed, withdrawal) the current results may be best seen as preliminary and further research is needed before causal inferences can be reached.

Associations between self-reported cannabis use frequency, potency, and cannabis/health metrics

BACKGROUND

Research shows that cannabis use frequency is associated with cannabis dependence and health metrics. However, much less is known about how self-reported cannabis potency (THC and CBD) may be associated with the same metrics, and whether any associations exist after accounting for frequency of cannabis use. Moreover, even less is known about how these relations may differ across cannabis product forms. This exploratory study examined 1) associations between cannabis frequency, potency, and cannabis/health metrics, and 2) whether associations between potency and cannabis/health metrics remained after controlling for frequency of use.

METHODS

Using a sample of adult recreational cannabis users in Colorado (N = 300), we tested the relationship between self-reported cannabis use metrics of frequency and potency of flower, edible, and concentrate products with separate measures of problematic cannabis use (i.e., dependence, withdrawal, craving), depression, anxiety, and general perceived health.

RESULTS

Greater frequency of flower and concentrate (but not edible) use were associated with greater problematic cannabis use, and greater concentrate use frequency was also associated with more mental health problems. Partial correlations controlling for average frequency of use across all product forms and CBD potency per product showed that one significant association between THC potency and cannabis/health metrics remained (i.e., higher THC concentrate potency with better health), and one emerged (i.e., higher THC concentrate potency with lower cannabis withdrawal).

CONCLUSIONS

Frequency of use is reliably associated with problematic cannabis use for flower and concentrates, but it did not account for all observed associations in this study. Differences in patterns of associations between frequency and potency and cannabis/health metrics across cannabis forms suggest a need for better understanding user reports of THC and CBD potency, individual differences among users, and improved measurement.

International Association for the Study of Pain Presidential Task Force on Cannabis and Cannabinoid Analgesia: research agenda on the use of cannabinoids, cannabis, and cannabis-based medicines for pain management

ABSTRACT

The President of the International Association for the Study of Pain established a task force on cannabis and cannabinoid analgesia to systematically examine the evidence on (1) analgesic pharmacology of cannabinoids and preclinical evidence on their efficacy in animal models of injury-related or pathological persistent pain; (2) the clinical efficacy of cannabis, cannabinoids, and cannabis-based medicines for pain; (3) harms related to long-term use of cannabinoids; as well as (4) societal issues and policy implications related to the use of these compounds for pain management. Here, we summarize key knowledge gaps identified in the task force outputs and propose a research agenda for generating high-quality evidence on the topic. The systematic assessment of preclinical and clinical literature identified gaps in rigor of study design and reporting across the translational spectrum. We provide recommendations to improve the quality, rigor, transparency, and reproducibility of preclinical and clinical research on cannabis and cannabinoids for pain, as well as for the conduct of systematic reviews on the topic. Gaps related to comprehensive understanding of the endocannabinoid system and cannabinoid pharmacology, including pharmacokinetics and drug formulation aspects, are discussed. We outline key areas where high-quality clinical trials with cannabinoids are needed. Remaining important questions about long-term and short-term safety of cannabis and cannabinoids are emphasized. Finally, regulatory, societal, and policy challenges associated with medicinal and nonmedicinal use of cannabis are highlighted, with recommendations for improving patient safety and reducing societal harms in the context of pain management.

Concentration of tetrahidrocannabinol in joints

Purpose

This study aims to assess the potency and dose of Δ-9-Tetrahidrocannabinol (THC) and Cannabidiol (CBD) in cannabis joints. This will enable better estimates of the degree of exposure in a user and contribute towards a better understanding of potential harmful effects.

Design/methodology/approach

Analysis of intact joints confiscated by law enforcement on the street in the autonomous region of Castilla y León (Spain) during the years 2017–2019.

Findings

This study analysed THC, CBN and CBD in marijuana joints (N = 744). Joints contain cannabis and tobacco (N = 729), had a median net weight 0.69 g (IQR = 0.28); concentration THC median was 6.30%(IQR = 4.51) and THC median dose 42 mg (IQR = 32.75). A total of 35.5% mixed joints contained CBN – median percentage 0.61% (IQR = 0.51). CBD was detected 10.3% of mixed joints – median percentage 0.13% (IQR = 0.12) and median dose 1 mg (IQR = 0.92). CBD/THC ratio presented median value of 0.02 (IQR = 0.02). The samples analysed comprised pure cannabis joints (N = 15), with THC median 11.86% (IWR = 6.30) or median dose of 118 mg.

Originality/value

The study found high values for concentration and dose of THC and CBD in cannabis joints, warning of high exposures for the user and associated potential consequences. The results obtained contribute new perspectives on the definition of a standard cannabis unit.

Assessing New Zealand's Cannabis Legalization and Control Bill: prospects and challenges

BACKGROUND

Few countries have developed detailed legislative proposals for legalizing cannabis. New Zealand recently released the Cannabis Legalization and Control Bill (CLCB) that will be the subject of a referendum in September 2020.

AIMS

To assess the CLCB, drawing on emerging evidence from cannabis legalization overseas, public health research on alcohol and tobacco and the attempt to establish a regulated market for 'legal highs' in New Zealand.

DISCUSSION

The CLCB proposes a strictly regulated commercial cannabis market that resembles the Canadian approach, but notably without on-line sales or regional heterogeneity in retail distribution. The objective of the CLCB of lowering cannabis use over time appears at odds with the largely commercial cannabis sector that will focus on expanding sales. The CLCB includes provision for home cultivation and social benefit operators, but it is not clear what priority these operators will receive. A potency cap of 15% tetrahydrocannabinol (THC) for cannabis plants is included, and this is at the high end of black-market cannabis. The proposed progressive product tax based on THC will be challenging to implement. There is no formal minimum price, but rather discretionary powers to raise the excise if the price drops too much. The CLCB includes a comprehensive ban on advertising, but non-conventional on-line promotion will be difficult to suppress. The central government cannabis authority is tasked with developing local retail outlet policies. We caution against the temptation to employ an interim regulatory regime following a positive referendum result, because a partially regulated market will expose users to health risks and undermine public support.

CONCLUSIONS

New Zealand's Cannabis Legalization and Control Bill's objective of reducing cannabis use via a commercial market will be challenging to achieve. The bill could be strengthened with formal minimum pricing, lower potency cap and greater clarity concerning social benefit operators and the role of local government.

ICan, an Internet-based intervention to reduce cannabis use: study protocol for a randomized controlled trial

Background

Heavy cannabis use is associated with adverse physical and mental health effects. Despite available effective treatments, the majority of heavy cannabis users does not seek professional help. Web-based interventions can provide an alternative for cannabis users who are reluctant to seek professional help. Several web-based cannabis interventions are effective in reducing cannabis use; however, the effect sizes are typically small and attrition rates are typically high. This suggests that web-based programs can be an effective cannabis use intervention for some, while others may need additional substance use treatment after completing a web-based intervention. Therefore, it is important that web-based interventions do not solely focus on reducing cannabis use, but also on improving attitudes towards substance use treatment. The Screening Brief Intervention and Referral to Treatment (SBIRT) approach appears to be well suited for the purpose of reducing cannabis use and improving substance use treatment utilization. Based on the SBIRT approach—and based on cognitive behavioral therapy (CBT) and motivational interviewing (MI)—we developed the Internet-based cannabis reduction intervention ICan.

Methods/design

This protocol paper presents the design of a randomized controlled trial (RCT) in which we evaluate the effectiveness of the ICan intervention compared to four online modules of educational information on cannabis in a sample of Dutch frequent cannabis users. The primary outcome measure is frequency of cannabis use. Secondary outcome measures include the quantity of cannabis used (grams), the attitudes towards seeking help and the number of participants who enter specialized treatment services for cannabis use-related problems.

Discussion

To the best of our knowledge, ICan is the first Internet-based intervention for cannabis users that combines screening, a brief intervention—based on CBT and MI—and referral to treatment options.

Trial registration

The study is registered in the Netherlands Trial Register; identifier NL7668. Registered on 17 April 2019.

Supporting Future Cannabis Policy - Developing a Standard Joint Unit: A Brief Back-Casting Exercise

The standardization of cannabis doses is a priority for research, policy-making, clinical and harm-reduction interventions and consumer security. Scientists have called for standard units of dosing for cannabis, similar to those used for alcohol. A Standard Joint Unit (SJU) would facilitate preventive and intervention models in ways similar to the Standard Drink (SD). Learning from the SD experiences allows researchers to tackle emerging barriers to the SJU by applying modern forecasting methods. During a workshop at the Lisbon Addictions Conference 2019, a back-casting foresight method was used to address challenges and achieve consensus in developing an SJU. Thirty-two professionals from 13 countries and 10 disciplines participated. Descriptive analysis of the workshop was carried out by the organizers and shared with the participants in order to suggest amendments. Several characteristics of the SJU were defined: (1) core values: easy-to use, universal, focused on THC, accurate, and accessible; (2) key challenges: sudden changes in patterns of use, heterogeneity of cannabis compounds as well as in administration routes, variations over time in THC concentrations, and of laws that regulate the legal status of recreational and medical cannabis use); and (3) facilitators: previous experience with standardized measurements, funding opportunities, multi-stakeholder support, high prevalence of cannabis users, and widespread changes in legislation. Participants also identified three initial steps for the implementation of a SJU by 2030: (1) Building a task-force to develop a consensus-based SJU; (2) Expanded available national-level data; (3) Linking SJU consumption to the concept of "risky use," based on evidence of harms.

Cannabis Consumption, Purchasing and Sources among Young Canadians: The Cannabis Purchase and Consumption Tool (CPCT)

BACKGROUND

Despite its extensive use, there is a paucity of research on consumption and purchasing patterns of cannabis, especially by modes of delivery.

OBJECTIVE

To assess the self-reported use and frequency of use of 12 different cannabis modes of delivery, their associated purchase sources, self-reported price, average consumption amount, and knowledge of THC and CBD levels.

METHODS

The Cannabis Purchase and Consumption Tool, an online survey, sampled Canadians 16-30 years old (N = 868) in October 2017. Final sample included participants reporting use of any mode of cannabis within the past 30-days (N = 185).

RESULTS

The most common modes of delivery were dried herb that was either smoked or vaporized, and cannabis edibles. Use of hashish, hash oil and other concentrates followed, while liquids, tinctures, topical ointments, and fresh flower/leaf were used less frequently. Average dried herb consumption was 17.8 g/month, 17.4 g/month, and 9.4 g/month among licensed medical, non-licensed medical, and non-medical cannabis users, respectively. At last time of purchase, participants paid an average of $17.97/gram for dried herb. 31.5% of current users reported knowing THC and 13.2% CBD levels of their cannabis.

CONCLUSIONS

Youth and young adults report a wide diversity of cannabis products and modes of administration. Traditional measures that rely primarily on frequency of use may be inadequate to assess the rapidly evolving cannabis market, particularly given policy changes, including legalization of non-medical cannabis.

Does cannabis alleviate tinnitus? A review of the current literature

OBJECTIVES

Endocannabinoid pathways have been proposed to affect the underlying pathophysiology of tinnitus. The aim of this study is to evaluate the scope and findings of existing literature on the relationship between cannabis and cannabinoid pathways and tinnitus.

METHODS

We conducted a review of animal, clinical and survey studies investigating the relationship between the use of cannabis-derived agents and tinnitus. Using pertinent keywords and MeSH terms on PubMed, relevant studies were identified, yielding four animal studies, two large cross-sectional survey studies, one clinical cross-over study, and one case report.

RESULTS

Animal studies revealed that cannabinoid receptor expression in the cochlear nucleus varied with tinnitus symptomatology and the use of cannabinoid agents either increased or had no effect on tinnitus-related behavior. Survey studies yielded conflicting results between cannabis use and tinnitus in the general population. Clinical data is largely lacking, although a small cohort study showed a dose-dependent relationship between tetrahydrocannabinol consumption and frequency of tinnitus episodes in patients receiving treatment for cancer.

CONCLUSION

While animal studies have revealed that cannabinoid receptors likely have a role in modulating auditory signaling, there is no compelling data either from animal or human studies for the use of cannabinoids to alleviate tinnitus. Further research is necessary to elucidate their precise role to guide development of therapeutic interventions.

LEVEL OF EVIDENCE

NA.

Knowledge of Tetrahydrocannabinol and Cannabidiol Levels Among Cannabis Consumers in the United States and Canada

Objective: This study aimed to examine consumer knowledge of tetrahydrocannabinol (THC) and cannabidiol (CBD) levels for usual cannabis products. Methods: Data are from the International Cannabis Policy Study conducted online in August-September 2018. Respondents included 6471 past 12-month cannabis users, aged 16-65 years, recruited from the Nielsen Global Insights Consumer Panel using nonprobability methods. Respondents were recruited from Canada, which had not yet legalized nonmedical cannabis (n=2354), and US states that had (n=2160) and had not (n=1957) legalized nonmedical cannabis. Results: Participants reported descriptive THC:CBD ratios (e.g., high THC, low CBD) and numeric THC and CBD levels (mg or %) for products they usually use in each of nine product categories. Few consumers knew and were able to report the numeric THC or CBD levels of their usual cannabis products. For example, only 10% of dried herb consumers reported the THC level, approximately 30% of whom reported implausible values. A greater proportion of consumers reported a descriptive THC:CBD ratio of their usual product, ranging from 50.9% of edible users to 78.2% of orally ingested oil users. Consumers were substantially more likely to report products high in THC versus low in THC for all products except topicals and tinctures, whereas similar proportions reported using products high and low in CBD. Despite some evidence of greater knowledge in legal jurisdictions, knowledge was still low in states with legal cannabis markets. Conclusions: Consumer knowledge of THC and CBD levels was low, with only modest differences between consumers living in jurisdictions that had and had not legalized nonmedical cannabis. The findings cast doubt on the validity of self-reported cannabinoid levels.

'Standard THC units': a proposal to standardize dose across all cannabis products and methods of administration

BACKGROUND AND AIMS

Cannabis products are becoming increasingly diverse, and vary considerably in concentrations of ∆⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD). Higher doses of THC can increase the risk of harm from cannabis, while CBD may partially offset some of these effects. Lower Risk Cannabis Use Guidelines currently lack recommendations based on quantity of use, and could be improved by implementing standard units. However, there is currently no consensus on how units should be measured or standardized among different cannabis products or methods of administration.

ARGUMENT

Existing proposals for standard cannabis units have been based on specific methods of administration (e.g. joints) and these may not capture other methods, including pipes, bongs, blunts, dabbing, vaporizers, vape pens, edibles and liquids. Other proposals (e.g. grams of cannabis) cannot account for heterogeneity in THC concentrations among different cannabis products. Similar to alcohol units, we argue that standard cannabis units should reflect the quantity of primary active pharmacological constituents (dose of THC). On the basis of experimental and ecological data, public health considerations and existing policy, we propose that a 'standard THC unit' should be fixed at 5 mg THC for all cannabis products and methods of administration. If supported by sufficient evidence in future, consumption of standard CBD units might offer an additional strategy for harm reduction.

CONCLUSIONS

Standard ∆⁹ -tetrahydrocannabinol (THC) units can potentially be applied among all cannabis products and methods of administration to guide consumers and promote safer patterns of use.

The state of clinical outcome assessments for cannabis use disorder clinical trials: A review and research agenda

There is considerable variability in the use of outcome measures in clinical trials for cannabis use disorder (CUD), and a lack of consensus regarding optimal outcomes may have hindered development and approval of new pharmacotherapies. The goal of this paper is to summarize an evaluation of assessment measures and clinical endpoints for CUD clinical trials, and propose a research agenda and priorities to improve CUD clinical outcome assessments. The primary recommendation is that sustained abstinence from cannabis should not be considered the primary outcome for all CUD clinical trials as it has multiple limitations. However, there are multiple challenges to the development of a reliable and valid indicator of cannabis reduction, including the lack of a standard unit of measure for the various forms of cannabis and products and the limitations of currently available biological and self-report assessments. Development of a core toolkit of assessments is needed to both allow flexibility for study design, while facilitating interpretation of outcomes across trials. Four primary agenda items for future research are identified to expedite development of improved clinical outcome assessments for this toolkit: (1) determine whether minimally invasive biologic assays could identify an acute level of cannabis use associated with psychomotor impairment or other cannabis-related harms; (2) create an indicator of quantity of cannabis use that is consistent across product types; (3) examine the presence of cannabis-specific functional outcomes; and (4) identify an optimal duration to assess changes in CUD diagnostic criteria.

The implications of late-life cannabis use on brain health: A mapping review and implications for future research

While medical and recreational cannabis use is becoming more frequent among older adults, the neurocognitive consequences of cannabis use in this age group are unclear. The aim of this literature review was to synthesize and evaluate the current knowledge on the association of cannabis use during older-adulthood with cognitive function and brain aging. We reviewed the literature from old animal models and human studies, focusing on the link between use of cannabis in middle- and old-age and cognition. The report highlights the gap in knowledge on cannabis use in late-life and cognitive health, and discusses the limited findings in the context of substantial changes in attitudes and policies. Furthermore, we outline possible theoretical mechanisms and propose recommendations for future research. The limited evidence on this important topic suggests that use in older ages may not be linked with poorer cognitive performance, thus detrimental effects of early-life cannabis use may not translate to use in older ages. Rather, use in old ages may be associated with improved brain health, in accordance with the known neuroprotective properties of several cannabinoids. Yet, firm conclusions cannot be drawn from the current evidence-base due to lack of research with strong methodological designs.

Is time elapsed between cannabis use and sleep start time associated with sleep continuity? An experience sampling method

BACKGROUND

A substantial proportion of people using cannabis report using it to improve sleep. Yet, little research exists on the associations between the timing of cannabis use and sleep. This study examines the time elapsed between cannabis use and sleep start time and its association with two of the main indicators of sleep continuity: (1) sleep onset latency (SOL) and (2) number of awakenings (NOA) throughout the night.

METHODS

Each morning, for 7 consecutive days, daily cannabis users (n = 54) reported on the timing of previous night's cannabis use and sleep indicators on their smartphones. Mixed effects models examined the relations of within- and between-subjects' time elapsed between previous night cannabis use and sleep start time, with (1) SOL and (2) NOA.

RESULTS

Within subjects, shorter time elapsed between cannabis use and sleep start time was associated with shorter SOL (β = 0.519, p = 0.010), but not NOA (β = -0.030, p = 0.535). Furthermore, between individuals, the time gap between the previous night cannabis use and sleep start time was not associated with SOL or NOA (p > 0.05).

CONCLUSIONS

It is possible that cannabis use proximal to bedtime is associated with shorted sleep onset latency but not nighttime awakenings. Cannabis users should be informed about both the potential sleep aid effects of cannabis and its limitations. Pending further evidence of the effects of cannabis on sleep, cannabis users experiencing sleep problems should be provided with evidence-based alternatives to improve sleep, e.g., pharmacological and behavioral treatments.

Daily patterns of substance use and violence among a high-risk urban emerging adult sample: Results from the Flint Youth Injury Study

OBJECTIVE

Interpersonal violence is a significant public health problem, with substance use a key risk factor. Intensive longitudinal methods (ILMs) provide data on daily patterns/relationships between substance use and violence, informing prevention. Prior daily research has not focused on these relationships among urban minority samples.

METHODS

Within an RCT comparing ILM assessment/schedule methods, 162-participants completed daily IVR (n = 81) or SMS (n = 81) assessments measuring 19 substance use and violence (partner/non-partner) behaviors daily for 90-days. GLMMs characterized between- and within-person predictors of daily violence.

RESULTS

Participants [48.7%-female; age = 24.4; 62.3%-African-American; 66.7%-public assistance] completed an average of 46.5 daily reports [SD = 26.7]. Across 90-days, alcohol was characterized by episodic weekend use (average = 10 days-of-use, 34.4% drinking-days involved binge-drinking), while marijuana use was continuous (average = 27 days-of-use; 1.7 times/day), with no weekend differences. Among 118-violent conflicts, 52.5% occurred on weekends; 57.6% were with non-partners/peers; 61.0% involved perpetration/57.6% victimization; and 52.5% involved severe violence. For violence conflicts, 27.1% were preceded by alcohol/22.9% preceded by drug use. Between-person predictors of daily violence included retaliatory attitudes (AOR = 3.2) and anxiety (AOR = 1.1). Within-person predictors included weekends (AOR = 1.6), binge drinking (AOR = 1.9), non-medical prescription opioid use (AOR = 3.5) and illicit drug use (AOR = 8.1).

CONCLUSION

Among a high-risk urban minority sample, we found that higher baseline retaliatory attitudes and anxiety, as well as same-day binge drinking, non-medical prescription opioid use, and illicit drug use were associated with daily violence, likely reflecting both pharmacological and socio-contextual factors. Addressing substance use and retaliatory violence with tailored prevention efforts may aid in decreasing negative interpersonal violence outcomes.

Cannabis use during methadone maintenance treatment for opioid use disorder: a systematic review and meta-analysis

BACKGROUND

Rates of cannabis use among patients receiving methadone maintenance therapy are high, and cannabis use may be associated with outcomes of methadone maintenance therapy. We examined the effect of cannabis use on opioid use in patients receiving methadone maintenance therapy to test the hypothesis that cannabis use is associated with a reduction in opioid use.

METHODS

In this systematic review, we searched MEDLINE/PubMed, Embase, PsycINFO, CINAHL and ProQuest Dissertations and Theses Global from inception to July 12, 2018. We summarized the effects of cannabis use on opioid use during methadone maintenance therapy and treatment retention. We conducted meta-analyses using a random effects model.

RESULTS

We included 23 studies in our review. We performed a meta-analysis of 6 studies, with a total number of participants of 3676, examining use of cannabis and opioids during methadone maintenance therapy. Owing to high heterogeneity, we described the studies qualitatively but provide the forest plots as supplemental material. The overall quality of evidence was very low, with a high risk of bias, owing to the nature of observational studies.

INTERPRETATION

We found no consensus among studies that cannabis use is associated with reduced opioid use or longer treatment retention when used during methadone maintenance therapy in patients with opioid use disorder. PROSPERO Registration: CRD42015029372.

Increasing potency and price of cannabis in Europe, 2006-16

AIMS

To quantify changes in (i) potency (concentration of Δ9 -tetrahydrocannabinol; %THC), (ii) price (euros/g of cannabis) and (iii) value (mg THC/euro) of cannabis resin and herbal cannabis in Europe.

DESIGN

Repeated cross-sectional study.

SETTING AND PARTICIPANTS

Data collected from 28 European Union (EU) member states, Norway and Turkey by the European Monitoring Centre for Drugs and Drug Addiction.

MEASUREMENTS

Outcome variables were potency, price and value for cannabis resin and herbal cannabis in Europe, 2006-16. Inflation was estimated using the Harmonised Indices of Consumer Prices. Mixed-effects linear regression models were used to estimate linear and quadratic time trends, with a random intercept and slope fitted to account for variation across countries.

FINDINGS

Resin potency increased from a mean [95% confidence interval (CI)] of 8.14% THC (6.89, 9.49) in 2006 to 17.22 (15.23, 19.25) in 2016. Resin price increased from 8.21 euros/g (7.54, 8.97) to 12.27 (10.62, 14.16). Resin increased in value, from 11.00 mg THC per euro (8.60, 13.62) to 16.39 (13.68, 19.05). Quadratic time trends for resin potency and value indicated minimal change from 2006 to 2011, followed by marked increases from 2011 to 2016. Herbal cannabis potency increased from 5.00% THC (3.91, 6.23) to 10.22 (9.01, 11.47). Herbal price increased from 7.36 euros/g (6.22, 8.53) to 12.22 (10.59, 14.03). The value of herbal cannabis did not change from 12.65 mg of THC per euro (10.18, 15.34) to 12.72 (10.73, 14.73). All price trends persisted after adjusting for inflation.

CONCLUSIONS

European cannabis resin and herbal cannabis increased in potency and price from 2006 to 2016. Cannabis resin (but not herbal cannabis) increased in the quantity of Δ9 -tetrahydrocannabinol per euro spent. Marked increases in resin potency and value from 2011 to 2016 are consistent with the emergence of new resin production techniques in European and neighbouring drug markets.

Effect of cannabis use in people with chronic non-cancer pain prescribed opioids: findings from a 4-year prospective cohort study

BACKGROUND

Interest in the use of cannabis and cannabinoids to treat chronic non-cancer pain is increasing, because of their potential to reduce opioid dose requirements. We aimed to investigate cannabis use in people living with chronic non-cancer pain who had been prescribed opioids, including their reasons for use and perceived effectiveness of cannabis; associations between amount of cannabis use and pain, mental health, and opioid use; the effect of cannabis use on pain severity and interference over time; and potential opioid-sparing effects of cannabis.

METHODS

The Pain and Opioids IN Treatment study is a prospective, national, observational cohort of people with chronic non-cancer pain prescribed opioids. Participants were recruited through community pharmacies across Australia, completed baseline interviews, and were followed up with phone interviews or self-complete questionnaires yearly for 4 years. Recruitment took place from August 13, 2012, to April 8, 2014. Participants were asked about lifetime and past year chronic pain conditions, duration of chronic non-cancer pain, pain self-efficacy, whether pain was neuropathic, lifetime and past 12-month cannabis use, number of days cannabis was used in the past month, and current depression and generalised anxiety disorder. We also estimated daily oral morphine equivalent doses of opioids. We used logistic regression to investigate cross-sectional associations with frequency of cannabis use, and lagged mixed-effects models to examine temporal associations between cannabis use and outcomes.

FINDINGS

1514 participants completed the baseline interview and were included in the study from Aug 20, 2012, to April 14, 2014. Cannabis use was common, and by 4-year follow-up, 295 (24%) participants had used cannabis for pain. Interest in using cannabis for pain increased from 364 (33%) participants (at baseline) to 723 (60%) participants (at 4 years). At 4-year follow-up, compared with people with no cannabis use, we found that participants who used cannabis had a greater pain severity score (risk ratio 1·14, 95% CI 1·01-1·29, for less frequent cannabis use; and 1·17, 1·03-1·32, for daily or near-daily cannabis use), greater pain interference score (1·21, 1·09-1·35; and 1·14, 1·03-1·26), lower pain self-efficacy scores (0·97, 0·96-1·00; and 0·98, 0·96-1·00), and greater generalised anxiety disorder severity scores (1·07, 1·03-1·12; and 1·10, 1·06-1·15). We found no evidence of a temporal relationship between cannabis use and pain severity or pain interference, and no evidence that cannabis use reduced prescribed opioid use or increased rates of opioid discontinuation.

INTERPRETATION

Cannabis use was common in people with chronic non-cancer pain who had been prescribed opioids, but we found no evidence that cannabis use improved patient outcomes. People who used cannabis had greater pain and lower self-efficacy in managing pain, and there was no evidence that cannabis use reduced pain severity or interference or exerted an opioid-sparing effect. As cannabis use for medicinal purposes increases globally, it is important that large well designed clinical trials, which include people with complex comorbidities, are conducted to determine the efficacy of cannabis for chronic non-cancer pain.

FUNDING

National Health and Medical Research Council and the Australian Government.

Effects of cannabis on eyewitness memory: A field study

Eyewitnesses to crimes are regularly under the influence of drugs, such as cannabis. Yet there is very little research on how the use of cannabis affects eyewitness memory. In the present study, we assessed the effects of cannabis on eyewitness recall and lineup identification performance in a field setting. One hundred twenty visitors of coffee shops in Amsterdam viewed a videotaped criminal event, were interviewed about the event, and viewed a target-present or target-absent lineup. Witnesses under the influence of cannabis remembered significantly fewer correct details about the witnessed event than did sober witnesses, with no difference in incorrect recall. Cannabis use was not significantly associated with lineup identification performance, but intoxicated witnesses were significantly better at judging whether their lineup identification was accurate. Theoretical and practical implications of the findings are discussed.

Quantifying cannabis: A field study of marijuana quantity estimation

The assessment of marijuana use quantity poses unique challenges. These challenges have limited research efforts on quantity assessments. However, quantity estimates are critical to detecting associations between marijuana use and outcomes. We examined accuracy of marijuana users' estimations of quantities of marijuana they prepared to ingest and predictors of both how much was prepared for a single dose and the degree of (in)accuracy of participants' estimates. We recruited a sample of 128 regular-to-heavy marijuana users for a field study wherein they prepared and estimated quantities of marijuana flower in a joint or a bowl as well as marijuana concentrate using a dab tool. The vast majority of participants overestimated the quantity of marijuana that they used in their preparations. We failed to find robust predictors of estimation accuracy. Self-reported quantity estimates are inaccurate, which has implications for studying the link between quantity and marijuana use outcomes. (PsycINFO Database Record

Time to acknowledge the mixed effects of cannabis on health: a summary and critical review of the NASEM 2017 report on the health effects of cannabis and cannabinoids

This is a summary and critical review of The National Academies of Sciences, Engineering and Medicine (NASEM) report of cannabis’ health effects. The report stated that effects of cannabis are understudied and research findings are mixed. It concluded that the under developed evidence base poses a public health risk and rightly addressed complications of cannabis research that need to be collaboratively resolved. We support NASEM’s urgent call for research, but add that the mixed evidence base cannot be solely attributed to research limitations. Rather, we propose a need to acknowledge the heterogeneity in cannabis’ effects to advance the field.

The potential impact of cannabis legalization on the development of cannabis use disorders

Specific provisions of legal cannabis legislation and regulation could influence cannabis initiation, frequency and quantity of use, and progression to cannabis use disorder. This brief essay highlights scientifically based principles and risk factors that underlie substance use and addiction that can be leveraged to inform policies that might mitigate the development and consequences of cannabis use disorder. Specifically, pharmacologic, access/availability, and environmental factors are discussed in relation to their influence on substance use disorders to illustrate how regulatory provisions can differentially affect these factors and risk for addiction. Relevant knowledge from research and experience with alcohol and tobacco regulation are also considered. Research designed to inform regulatory policy and to evaluate the impact of cannabis legislation on cannabis use and problems is progressing. However, definitive findings will come slowly, and more concerted efforts and resources are needed to expedite this process. In the meantime, policymakers should take advantage of the large body of scientific literature on substance use to foster empirically-guided, common sense approaches to cannabis policy that focus on prevention of addiction.

Associations between butane hash oil use and cannabis-related problems

BACKGROUND

High-potency cannabis concentrates are increasingly popular in the United States, and there is concern that use of high-potency cannabis might increase risk for cannabis-related problems. However, little is known about the potential negative consequences of concentrate use. This study reports on associations between past-year use of a high-potency cannabis concentrate, known as butane hash oil (BHO), and cannabis-related problems.

METHODS

A sample of 821 college students were recruited to complete a survey about their health and behavior. Participants who had used cannabis in the past year (33%, n=273) completed questions about their cannabis use, including their use of BHO and cannabis-related problems in eight domains: physical dependence, impaired control, academic-occupational problems, social-interpersonal problems, self-care problems, self-perception, risk behavior, and blackouts.

RESULTS

Approximately 44% (n=121) of past-year cannabis users had used BHO in the past year. More frequent BHO use was associated with higher levels of physical dependence (RR=1.8, p<0.001), impaired control (RR=1.3, p<0.001), cannabis-related academic/occupational problems (RR=1.5, p=0.004), poor self-care (RR=1.3, p=0.002), and cannabis-related risk behavior (RR=1.2, p=0.001). After accounting for sociodemographic factors, age of onset of cannabis use, sensation seeking, overall frequency of cannabis use, and frequency of other substance use, BHO use was still associated with higher levels of physical dependence (RR=1.2, p=0.014).

CONCLUSIONS

BHO use is associated with greater physiological dependence on cannabis, even after accounting for potential confounders. Longitudinal research is needed to determine if cannabis users with higher levels of physiological dependence seek out BHO and/or if BHO use increases risk for physiological dependence.

User characteristics and effect profile of Butane Hash Oil: An extremely high-potency cannabis concentrate

BACKGROUND

Recent reports suggest an increase in use of extremely potent cannabis concentrates such as Butane Hash Oil (BHO) in some developed countries. The aims of this study were to examine the characteristics of BHO users and the effect profiles of BHO.

DESIGN

Anonymous online survey in over 20 countries in 2014 and 2015. Participants aged 18 years or older were recruited through onward promotion and online social networks. The overall sample size was 181,870. In this sample, 46% (N=83,867) reported using some form of cannabis in the past year, and 3% reported BHO use (n=5922).

MEASUREMENTS

Participants reported their use of 7 types of cannabis in the past 12 months, the source of their cannabis, reasons for use, use of other illegal substances, and lifetime diagnosis for depression, anxiety and psychosis. Participants were asked to rate subjective effects of BHO and high potency herbal cannabis.

FINDINGS

Participants who reported a lifetime diagnosis of depression (OR=1.15, p=0.003), anxiety (OR=1.72, p<0.001), and a larger number of substance use (OR=1.29, p<0.001) were more likely to use BHO than only using high potency herbal cannabis. BHO users also reported stronger negative effects and less positive effects when using BHO than high potency herbal cannabis (p<0.001) CONCLUSION: Mental health problems and other illicit drug use were associated with use of BHO. BHO was reported to have stronger negative and weaker positive effects than high potency herbal cannabis.

Daily associations between cannabis motives and consumption in emerging adults

BACKGROUND

Increasing rates of cannabis use among emerging adults is a growing public health problem. Intensive longitudinal data can provide information on proximal motives for cannabis use, which can inform interventions to reduce use among emerging adults.

METHOD

As part of a larger longitudinal study, patients aged 18-25 years (N=95) recruited from an urban Emergency Department completed daily text message assessments of risk behaviors for 28days, including daily cannabis quantity and motives. Using a mixed effects linear regression model, we examined the relationships between daily quantity of cannabis consumed and motives (i.e., enhancement, social, conformity, coping, and expansion).

RESULTS

Participants were, on average, 22.0 years old (SD=2.2); 48.4% were male, 45.3% were African American, and 56.8% received public assistance. Results from the multi-level analysis (clustering day within individual), controlling for gender, race, and receipt of public assistance, indicated daily use of cannabis use for enhancement (β=0.27), coping (β=0.15), and/or social motives (β=0.34) was significantly associated with higher quantities of daily cannabis use; whereas expansion and conformity motives were not.

CONCLUSIONS

Daily data show that emerging adults who use cannabis for enhancement, social, and coping motives reported using greater quantities of cannabis. Future research should examine more comprehensive cannabis motives (e.g., boredom, social anxiety, sleep) and test tailored interventions focusing on alternative cognitive/behavioral strategies to address cannabis motives.

Anatomy of a Joint: Comparing Self-Reported and Actual Dose of Cannabis and Tobacco in a Joint, and How These Are Influenced by Controlled Acute Administration

Introduction: Major gaps exist in the measurement of cannabis exposure. The accuracy of self-reported cannabis and tobacco dose per joint is poorly characterized and has never been investigated following acute cannabis/tobacco exposure. Using an innovative "Roll a Joint" paradigm, this study aims to (1) compare estimated and actual dose of cannabis and tobacco per joint at baseline and (2) examine the acute effects of cannabis and/or tobacco on estimated and actual dose. Materials and Methods: We investigated this by using a randomized, double-blind, placebo-controlled crossover 2 (active cannabis, placebo cannabis)×2 (active tobacco, placebo tobacco) design in a laboratory setting. Participants were 24 recreational cousers of cannabis and tobacco. At baseline, they were asked to measure out the amount of cannabis and tobacco they would put in an average joint for themselves (dose per joint). Then, on each of four drug administration sessions, participants were again asked to do this for a joint they would want to smoke "right now." Self-reported and actual amount was recorded (g). Results: At baseline, the estimated amount of cannabis per joint (0.28±0.23 g) was double the actual amount (0.14±0.12 g) (p=0.003, d=0.723). No difference emerged between estimated (0.43±0.25 g) and actual (0.35±0.15 g) (p=0.125) amount of tobacco per joint. Compared to placebo, active cannabis reduced the actual dose of both cannabis (p=0.035) and tobacco (p<0.001) they put in a joint. Participants accurately estimated this reduction for tobacco (p=0.014), but not for cannabis (p=0.680). Conclusions: Self-reported dose per joint is accurate for tobacco but dramatically overestimates cannabis exposure and therefore should be viewed with caution. Cannabis administration reduced the amount of cannabis and tobacco added to joints, suggesting a reduction in dose during a smoking session. The "Roll A Joint" paradigm should be implemented for better accuracy in assessing dose per joint.

Can we make cannabis safer?

Cannabis use and related problems are on the rise globally alongside an increase in the potency of cannabis sold on both black and legal markets. Additionally, there has been a shift towards abandoning prohibition for a less punitive and more permissive legal stance on cannabis, such as decriminalisation and legalisation. It is therefore crucial that we explore new and innovative ways to reduce harm. Research has found cannabis with high concentrations of its main active ingredient, δ-9-tetrahydrocannabinol (THC), to be more harmful (in terms of causing the main risks associated with cannabis use, such as addiction, psychosis, and cognitive impairment) than cannabis with lower concentrations of THC. By contrast, cannabidiol, which is a non-intoxicating and potentially therapeutic component of cannabis, has been found to reduce the negative effects of cannabis use. Here, we briefly review findings from studies investigating various types of cannabis and discuss how future research can help to better understand and reduce the risks of cannabis use.

The Standard Joint Unit

OBJECTIVE

Reliable data on cannabis quantities is required to improve assessment of cannabis consumption for epidemiological analysis and clinical assessment, consequently a Standard Joint Unit (SJU) based on quantity of 9-Tetrahydrocannabinol (9-THC) has been established.

METHODOLOGY

Naturalistic study of a convenience sample recruited from February 2015-June 2016 in universities, leisure spaces, mental health services and cannabis clubs in Barcelona. Adults, reporting cannabis use in the last 60 days, without cognitive impairment or language barriers, answered a questionnaire on cannabis use and were asked to donate a joint to further determine their 9-THC and Cannabidiol (CBD) content.

RESULTS

492 participants donated 315 valid joints. Donators were on average 29 years old, mostly men (77%), single (75%), with at least secondary studies (73%) and in active employment (63%). Marijuana joints (N=232) contained a median of 6.56mg of 9-THC (Interquartile range-IQR=10,22) and 0.02mg of CBD (IQR=0.02); hashish joints (N=83) a median of 7.94mg of 9-THC (IQR=10,61) and 3.24mg of CBD (IQR=3.21). Participants rolled 4 joints per gram of cannabis and paid 5€ per gram (median values).

CONCLUSION

Consistent 9-THC-content in joints lead to a SJU of 7mg of 9-THC, the integer number closest to the median values shared by both cannabis types. Independently if marijuana or hashish, 1 SJU = 1 joint = 0.25 g of cannabis = 7 mg of 9-THC. For CBD, only hashish SJU contained relevant levels. Similarly to the Standard Drink Unit for alcohol, the SJU is useful for clinical, epidemiological and research purposes.

The Effects of Acute Cannabis Use on Nontraffic Injury Risk: Reviewing the Available Literature and Identifying Ways Forward

Recent evidence has indicated that cannabis use before driving is associated with a modest but increased risk for traffic-related injuries. However, the question of whether recent cannabis use is associated with a greater risk for other types of injuries remains unanswered. Aiming to understand better how acute cannabis use might affect the risk for all causes of injury, we have summarized the limited data available in the literature on the risk of non-traffic injuries associated with recent cannabis use. Very few studies were able to provide estimate risks for all injuries or injuries other than those related to road traffic injuries, with the limited evidence available showing mixed findings. The only significant risk found (in only one study) suggests an inverse association between all injuries and cannabis use. Study designs are limited, and the majority of studies have neither data on acute cannabis use among injured individuals nor a valid control group for estimating injury risk attributable to cannabis. In conclusion, studies of the association between cannabis and non-traffic injuries present several limitations, particularly regarding sampling strategies, injury risk assessment for different causes of injury, and a dose-response risk relationship with injury. Further studies, incorporating better design for different causes of injury and drug testing, are required to reach firmer conclusions on the association between cannabis use and non-traffic injury risk.