Predictive validity of cannabis consumption measures: Results from a national longitudinal study

Examining Associations Between Cannabis Use Disorder and Measures of Weekly and Within-Day Cannabis Frequency, Quantity, and Potency in College Students

Background: College student cannabis use has increased significantly in recent years, and individuals aged 18-25 are at elevated risk for development of cannabis use disorder (CUD). While weekly cannabis use frequency is a commonly used measure of cannabis consumption, there is increasing scientific interest in exploring more nuanced measures of cannabis use. Currently, limited research exists examining the clinical utility of cannabis quantity, within-day frequency, and potency variables. Methods: We used cross-sectional survey data from a sample of 617 undergraduate students in the state of Colorado. A two-part model-building approach was leveraged to examine whether within-session cannabis quantity and within-day cannabis use frequency were associated with odds of experiencing any CUD symptoms and total number of CUD symptoms endorsed. We also examined whether cannabis flower potency was associated with odds of experiencing any CUD symptoms and total number of CUD symptoms endorsed among a subset (N=288) of the sample who reported knowledge of the cannabinoid content of their most frequently used products. Results: Weekly flower use frequency (odds ratio [OR]=1.27, p<0.001) and weekly concentrate use frequency (OR=1.10, p=0.044) were positively associated with increased odds of experiencing any CUD symptoms, but cannabis quantity and within-day frequency variables were not. In addition, no association was found between flower potency and odds of endorsing any CUD symptoms. Among individuals endorsing at least one symptom, weekly flower use frequency (incident rate ratio [IRR]=1.06, p<0.001) was positively associated with total symptom count, but weekly concentrate use frequency, cannabis quantity variables, and within-day frequency variables were not. Among individuals endorsing symptoms, a positive association was found between flower potency and total symptom count (IRR=1.01, p=0.008). Conclusion: Current methods of assessing within-session cannabis quantity and within-day cannabis use frequency may lack clinical utility in examining college student CUD symptoms over and above weekly cannabis use frequency. Cannabis flower potency may prove useful in assessment of CUD symptom severity, but further research is warranted.

Australian daily cannabis users' use of police avoidance strategies and compensatory behaviours to manage the risks of drug driving

INTRODUCTION

Daily use of cannabis is increasing in Australia, yet there is limited understanding of the driving behaviours within this cohort, including how they perceive and manage the risks of being apprehended for drug driving and involved in a crash after consumption.

METHODS

An online survey was completed by 487 Australians who reported daily cannabis use (30% medically prescribed patients, 58% male).

RESULTS

Current drug driving (i.e., driving within 4 h of consuming cannabis each week) was reported by 86% of participants. Future drug driving was anticipated by 92% of the sample. While most participants (93%) disagreed that their risk of crash increased following cannabis use, participants reported that they would drive more carefully (89%), leave greater headway (79%) and/or drive slower (51%) following cannabis consumption. Half of the sample (53%) perceived the risk of apprehension for drug driving to be likely to some extent. Strategies to reduce the likelihood of being detected were used by 25% of participants, and included using Facebook police location sites (16%), driving on back roads (6%) and/or consuming substances to mask the presence of drugs (13%). The regression analysis revealed that individuals who reported more occasions of cannabis use per day, and who perceived that cannabis does not reduce driving ability, reported a greater extent of current drug driving.

DISCUSSION AND CONCLUSIONS

Interventions and education which aim to challenge this perception that 'cannabis does not reduce driving ability' may prove important for reducing drug driving among the most frequent consumers of cannabis.

Prevalence and correlates of cannabis use disorder among Australians using cannabis products to treat a medical condition

INTRODUCTION

Prior research has examined the prevalence and correlates of cannabis use disorder (CUD) in people who use cannabis; however, these are poorly described for people using cannabis for medical reasons.

METHODS

Data came from a 2018 to 2019 online, anonymous, cross-sectional survey of Australians reporting using either illicit or licit cannabis for medical reasons within the past year. Included were questions on demographics, current and lifetime patterns of cannabis use, clinical conditions for which medical cannabis was used, and individual criteria for CUD and cannabis withdrawal syndrome. Bayesian Horseshoe logistic regression models were used to identify covariates associated with meeting CUD DSM-5 conditions for any-CUD (≥2/11 criteria) and moderate-severe-CUD (≥4/11).

RESULTS

A total of 905 participants were included in the analysis. The majority (98%) used illicit cannabis products. Criteria for any-CUD criteria were met by 290 (32.0%), and 117 (12.9%) met criteria for moderate-severe-CUD. Tolerance (21%) and withdrawal (35%) were the most commonly met criteria. Correlates with the strongest association with CUD were inhaled route of administration [odds ratio (OR) = 2.96, 95% credible interval 1.11, 7.06], frequency of cannabis use (OR = 1.24, 1.11-1.35), proportion of cannabis for medical reasons (OR = 0.83, 0.74, 0.94), frequency of tobacco use (OR = 1.10, 1.03, 1.17), age (OR = 0.75, 0.64, 0.90) and pain as main clinical indication (OR = 0.58, 0.36, 1.00).

DISCUSSION AND CONCLUSIONS

Prevalence of CUD in medical cannabis users appears comparable to 'recreational' users, with many similar correlates. CUD was associated with using cannabis to treat mental health rather than pain conditions and inhaled over other routes of administration.

Risky decision-making as an antecedent or consequence of adolescent cannabis use: findings from a 2-year longitudinal study

BACKGROUND AND AIMS

Although poor decision-making (DM) has been correlated with problematic cannabis use (CU), cross-sectional designs make it difficult to determine whether poor DM represents an antecedent and/or consequence of CU. The current study measured bidirectional associations between CU and DM among adolescents over 2 years and compared these findings to those observed with episodic memory, which is consistently reported as a consequence of CU. We also measured the role of DM as a risk factor for cannabis use disorder (CUD) onset.

DESIGN

Two-year longitudinal study with five bi-annual assessments.

PARTICIPANTS

Participants were 401 adolescents aged 14-17 years at baseline.

SETTING

Miami, Florida, USA.

MEASUREMENTS

CU frequency and CUDs were assessed at each time-point through the Drug Use History Questionnaire and Structured Clinical Interview for DSM-IV, respectively. Neurocognition was assessed at odd time-points throughout the Iowa Gambling Task, Game of Dice Task and Cups Task [decision-making (DM)] and the Wechsler Memory Scale IV and California Verbal Learning Test II (episodic memory). We used latent growth curve modeling to examine bidirectional influences between CU and neurocognition over time. We applied discrete time survival analyses to determine whether baseline DM predicted CUD onset.

FINDINGS

Greater lifetime CU frequency was associated with poorer episodic memory at baseline (bs = -14.84, -16.44, Ps = 0.038, 0.021). Greater CU escalation predicted lesser gains in immediate episodic memory (b = -0.05, P = 0.020). Baseline DM did not predict CU escalation (b = 0.07, P = 0.421), nor did escalation in CU predict changes in DM (b = 0.02, P = 0.352). Baseline DM also did not predict CUD onset (adjusted OR = 1.01, 95% confidence interval = 0.98-1.06).

CONCLUSIONS

This study replicates findings that poorer episodic memory in adolescents appears to be a consequence of cannabis use, even among adolescents at earlier stages of use. Poor decision-making does not appear to be either a consequence of or a risk factor for escalating cannabis use or onset of cannabis use disorder among adolescents.

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.

Quantity and frequency of cannabis use in relation to cannabis-use disorder and cannabis-related problems

BACKGROUND

In almost all of the literature examining the relation between cannabis use and cannabis-related harms, researchers have neglected to include quantity measures of cannabis use. The study aims to assess whether cannabis: (1) quantity predicts harms; and (2) quantity might interact with other key variables (age, gender, and frequency of use) vis-à-vis the outcomes.

METHOD

Using the 2012-2013 National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III), the current study (n = 36,309; n = 3,339 past-year cannabis users) employed a logistic-regression approach to assess the cross-sectional relations between the continuous variables of cannabis-use quantity and frequency and two Alcohol Use Disorder and Associated Disabilities Interview Schedule-5 (AUDADIS-5) DSM-5-based outcomes: past-year cannabis-use disorder (CUD) and past-year cannabis-related problems (CRP).

RESULTS

In the CUD model, the key variables log quantity [OR = 1.98 (95 % CI, 1.64;2.39), p < 0.001], log frequency [OR = 1.78 (95 % CI, 1.62;1.96), p < 0.001] and the log-quantity-by-log-frequency interaction [OR = 0.83 (95 % CI, 0.75;0.93), p = 0.002] were statistically significant. The final CRP model included the following main predictors: log quantity [OR = 2.13 (95 % CI, 1.70;2.66), p = <0.001], log frequency [OR = 1.50 (95 % CI, 1.36;1.65), p = <0.001], and a log-quantity-by-log-frequency interaction [OR = 0.82 (95 % CI, 0.73;0.93), p = 0.002].

CONCLUSIONS

The quantity-by-frequency interactions in both models showed that the relative effect of quantity on cannabis-use disorders and cannabis-related problems decreased as frequency increased, and vice versa.

Examining measurement reactivity in daily diary data on substance use: Results from a randomized experiment

The debate about whether measurement reactivity exists in daily diary research on substance use is still unsettled due to the issues of study design and statistical methodology. This study proposes a time-varying effect model (TVEM) that characterizes the trajectory of substance use behaviors with nonparametric functions determined by the data rather than imposes presumed parametric functions. It also allows researchers to investigate the effect of measurement reactivity on not only the likelihood of using substances but also the amount of substance use. The TVEM was applied to analyze diary data on alcohol and marijuana use collected from an experiment, which randomized 307 participants in Michigan into daily and weekly assessment schedules during 2014-2016. This study found short-term measurement reactivity on alcohol use, but did not find a significant reactivity effect on marijuana use. The daily group had smaller odds of abstinence from drinking but lower expected drinking quantity in the first week of assessment, which dissipated by the second week. The results indicate that although daily self-monitoring could have short-term reactivity on substance use behaviors that tend to fluctuate across days, such as alcohol use, it does not affect substance use behaviors that are quite consistent, such as marijuana use. Our findings imply that although daily monitoring of drinking may motivate people to reduce the quantity consumed once they start to drink, it may also arouse their desire to start drinking. Yet, both effects tend to last only one week, as participants accommodate to the monitoring by the second week.

Measuring Within-Individual Cannabis Reduction in Clinical Trials: A Review of the Methodological Challenges

Purpose

Cannabis abstinence traditionally is the primary outcome in cannabis use disorder (CUD) treatment trials. Due to the changing legality of cannabis, patient goals, and preliminary evidence that suggests individuals who reduce their cannabis use may show functional improvements, cannabis reduction is a desirable alternative outcome in CUD trials. We review challenges in measuring cannabis reduction and the evidence to support various definitions of reduction.

Findings

Reduction in number of cannabis use days was associated with improvements in functioning across several studies. Reductions in quantity of cannabis used was inconsistently associated with improvements in functioning, though definitions of quantity varied across studies. Different biomarkers may be used depending on the reduction outcome.

Conclusions

Biologically-confirmed reductions in frequency of cannabis use days may represent a viable endpoint in clinical trials for cannabis use disorder. Additional research is needed to better quantify reduction in cannabis amounts.

Systematic review of outcome domains and measures used in psychosocial and pharmacological treatment trials for cannabis use disorder

Cannabis use disorder (CUD) is prevalent and demand for treatment is increasing, yet few individuals engage in formal treatment and the efficacy of established interventions for CUD is modest. Existing clinical trials evaluating psychosocial and pharmacological treatments for CUD have incorporated a wide variety of measures for assessing cannabis use outcomes, including abstinence, self-reported frequency and quantity used, withdrawal, use/dependence severity, and other psychosocial outcomes. The heterogeneity of measures and outcomes has limited quantitative analyses of the comparative effectiveness of existing interventions. The purpose of this systematic review is to: 1) identify and characterize approaches for measuring cannabis use in existing CUD intervention trials, including abstinence, frequency and quantity of use, and 2) summarize measures used to assess treatment efficacy in other outcome domains (e.g., cannabis use severity, psychosocial functioning, cannabis withdrawal), and provide a platform for future research to evaluate which outcome measures are most likely to reflect treatment efficacy and clinically significant improvement in other outcome domains.