Teen Reports of Cannabis for Medical Reasons-What Does That Mean?

Does cannabis substitute or complement alcohol after recreational cannabis legalization in the Washington State? A three-level mixed-effects modeling

BACKGROUND

Whether cannabis substitute or complement alcohol remains inconclusive. Little is known about the daily-level associations between cannabis and alcohol use by cannabis user type (medical vs. recreational use) in people who use alcohol and cannabis within a legalized environment.

METHODS

Adult participants were from four waves of Washington Panel Survey during 2014-2016, who consumed both cannabis and alcohol in the past six months. Daily measurements of alcohol and cannabis use in the past week were collected at each wave. Our outcome variable was continuous alcoholic drinks, the exposure was any cannabis use. We applied three-level negative binomial models to account for within-person wave-to-wave and between-person variations, deriving pure within-person within-wave associations between cannabis and alcohol use at the daily level. A cross-level interaction between day-level cannabis use and wave-level medical cannabis recommendation investigated the potential differential substitution/complementarity patterns by medical recommendation status.

RESULTS

259 respondents with 440 person-waves and 3,051 daily observations were included. We found a statistically significant pure Level 1 (within-person daily-level) effect of cannabis use among recreational cannabis users (IRR = 1.37, 95 % CI: 1.05-1.79, p = 0.02), showing a complementary use pattern. We also found a statistically significant cross-level interaction between medical cannabis recommendation and cannabis use at Level 1 (IRR = 0.57, 95 % CI: 0.34-0.96, p = 0.03), indicating that, differently from recreational users, medical cannabis users may have a substitution use pattern.

CONCLUSIONS

Cannabis user type may inform co-use patterns. This study suggested recreational cannabis users tended to use alcohol and cannabis in a complementary manner in Washington State following the legalization of recreational use.

Simultaneous Cannabis and Alcohol Use among Medical Cannabis Patients

Background: During the past two decades of cannabis legalization, the prevalence of medical cannabis (MC) use has increased and there has also been an upward trend in alcohol consumption. As less restricted cannabis laws generate more adult cannabis users, there is concern that more individuals may be simultaneously using medical cannabis with alcohol. A few studies have examined simultaneous use of medical cannabis with alcohol, but none of those studies also assessed patients' current or previous non-medical cannabis use. This paper explores simultaneous alcohol and medical cannabis use among medical cannabis patients with a specific focus on previous history of cannabis use and current non-medical cannabis use. Methods: A retrospective cohort study of MC patients (N = 319) from four dispensaries located in New York. Bivariate chi-square tests and multivariable logistic regression are used to estimate the extent to which sociodemographic and other factors were associated with simultaneous use. Results: Approximately 29% of the sample engaged in simultaneous use and a large share of these users report previous (44%) or current (66%) use of cannabis for non-medical purposes. MC patients who either previously or currently use cannabis non-medicinally, men, and patients using MC to treat a pain-related condition, were significantly more likely to report simultaneous alcohol/MC use. Conclusions: Findings indicate that there may be differential risks related to alcohol/MC use, which should be considered by cannabis regulatory policies and prevention/treatment programs. If patients are using cannabis and/or alcohol to manage pain, clinicians should screen for both alcohol and cannabis use risk factors.

Patterns of Cannabis and Alcohol Co-Use: Substitution Versus Complementary Effects

PURPOSE

The purpose of this review is to discuss the literature regarding the concurrent use (co-use) of alcohol and cannabis and competing hypotheses as to whether cannabis acts as a substitute for (i.e., replacing the effects of alcohol, resulting in decreased use) or a complement to (i.e., used to enhance the effects of alcohol, resulting in increased use) alcohol. The impact of cannabis use on alcohol-related outcomes has received increased attention in the wake of ongoing legalization of cannabis for both medical and recreational purposes. Evidence for both hypotheses exists in the literature across a broad range of data collection methods and samples and is carefully reviewed here. In addition, various mechanisms by which cannabis may act as an alcohol substitute or complement are explored in depth with the goal of better understanding equivocal findings.

SEARCH METHODS

This review includes articles that were identified from a search for studies on alcohol and cannabis co-use, with a specific focus on studies exploring complementary versus substitution aspects of co-use. Search terms were included in Google Scholar, PsycINFO, MEDLINE, and Web of Science. Eligible studies were those that measured alcohol and cannabis co-use in human samples in laboratory, survey, or ecological momentary assessment studies, or that directly referenced substitution or complementary patterns of use.

SEARCH RESULTS

Search results returned 650 articles, with 95 meeting inclusion criteria.

DISCUSSION AND CONCLUSIONS

Results of this review reveal compelling evidence for both substitution and complementary effects, suggesting nuanced yet significant distinctions across different populations examined in these studies. Several mechanisms for the impact of cannabis use on alcohol-related outcomes are identified, including patterns and context of co-use, timing and order of use, cannabinoid formulation, pharmacokinetic interactions, and user characteristics (including diagnostic status), all of which may influence substitution versus complementary effects. This review will inform future research studies examining this topic in both clinical and community samples and aid in the development of treatment and prevention efforts targeting those populations most vulnerable to negative consequences of co-use. Finally, this review highlights the need for additional research in more diverse samples and the use of mixed-methods designs to examine both pharmacological and contextual influences on co-use.