Risk of Persistence and Progression of Use of 5 Cannabis Products After Experimentation Among Adolescents

Jessica L. Barrington-Trimis, PhD; Junhan Cho, PhD; Esthelle Ewusi-Boisvert, BA; Deborah Hasin, PhD; Jennifer B. Unger, PhD; Richard A. Miech, PhD; Adam M. Leventhal, PhD

JAMA Network Open, 2020, 3, (1), e1919792.

doi : 10.1001/jamanetworkopen.2019.19792

 

Abstract

IMPORTANCE : While a diverse array of cannabis products that may appeal to youth is currently available, it is unknown whether the risk of persistent cannabis use and progression to higher frequency of use after experimentation differs among cannabis products.

OBJECTIVE : To estimate the comparative relative risk of experimental use of 5 cannabis products on use status and frequency of use among adolescents during 12 months of follow-up.

DESIGN, SETTING, AND PARTICIPANTS : In this cohort study, data were collected from 3065 adolescents at 10 high schools in southern California, with baseline data collected in spring 2016, when studentswere in 11th grade, and 6-month and 12-month follow-up surveys collected in fall 2016 and spring 2017, when students were in 12th grade. Analyses, conducted from April to June 2019, were restricted to 2685 participants whowere light or nonusers of any cannabis product (ie,2 days in the past 30 days) at baseline.

EXPOSURES : Number of days of use of each cannabis product (ie, combustible, blunts, vaporized, edible, or concentrated) in the past 30 days at baseline (ie, 1-2 vs 0 days).

MAIN OUTCOMES AND MEASURES : Past 6-month use (ie, yes vs no) and number of days of use in the past 30 days at 6-month and 12-month follow-ups for each product.

RESULTS : Of 2685 individuals in the analytic sample, 1477 (55.0%) were young women, the mean (SD) age was 17.1 (0.4) years, and a plurality (1231 [46.6%]) were Hispanic individuals. Among them, 158 (5.9%) reported combustible cannabis use on 1 to 2 days of the past 30 days at baseline, 90 (3.4%) reported blunt use, 78 (2.9%) reported edible cannabis use, 17 (0.6%) reported vaping cannabis, and 15 (0.6%) reported using cannabis concentrates. In regression models adjusting for demographic characteristics and poly–cannabis product use, statistically stronger associations of baseline use with subsequent past 6-month use at the 6-month and 12-month follow-ups were observed for combustible cannabis use (odds ratio, 6.01; 95%CI, 3.66-9.85) and cannabis concentrate use (odds ratio, 5.87; 95%CI, 1.18-23.80) compared with use of blunts (OR, 2.77; 95%CI, 1.45-5.29) or edible cannabis (OR, 3.32; 95%CI, 1.86-5.95) (P for comparison < .05); vaporized cannabis use (OR, 5.34; 95%CI, 1.51-11.20) was not significantly different from the other products. In similarly adjusted models, we found the association of cannabis use at baseline with mean days of use at the 6-month and 12-month follow up was significantly stronger for cannabis concentrate than for other cannabis products; participants who had used cannabis concentrate on 1 to 2 of the past 30 days at baseline (vs 0 days) used cannabis concentrate a mean of 9.42 (95%CI, 2.02-35.50) more days in the past 30 days at the 6-month and 12 month follow-ups (P for comparison < .05).

CONCLUSIONS AND RELEVANCE : Cannabis control efforts should consider targeting specific cannabis products, including combustible cannabis and cannabis concentrate, for maximum public health consequences.

 

Key Points

Question : After experimentation in adolescence, do risks of progression and persistence of cannabis use during a 12-month follow-up period differ among 5 cannabis products ?

Findings : In this cohort study of 2685 adolescents with no history of heavy cannabis use, after accounting for polyuse of multiple products, the association of baseline experimental use with persistent use and progression of use of that product during a 12-month follow-up period was significantly stronger for cannabis concentrate than for other cannabis products.

Meaning : The rate of persistence and progression after experimentation among adolescents may be amplified with the use of cannabis concentrate compared with other cannabis products

 

Introduction

The legalization and commercialization of cannabis have increased the diversity of the types of cannabis products in the marketplace. While combustible cannabis (eg, smoking cannabis in a joint or bong) and edible cannabis (eg, consumption of cannabis-infused food items) date back centuries or more,1 other cannabis formulations have more recently become available. Cannabis concentrates (eg, dabbing or use of highly concentrated cannabis products, commonly referred to as wax, shatter, budder, or butane hash oil) first gained popularity around 2010 and were notable for high concentrations of tetrahydro-cannabinol (THC), the primary psychoactive ingredient in cannabis.2

Levels of THC in cannabis concentrate were 2 to 4 times greater than those found in traditional cannabis products, reaching concentrations greater than 80% THC.2 With the recent advent and rapid rise to popularity of personal electronic vaping devices,3 they have become another popular vehicle for use of high concentrations of cannabis in the form of dry herb, THC e-liquid solutions, or cannabis concentrate solutions.4

Many youth experiment with cannabis during adolescence; in 2018, 43.6%of students in 12th grade reported ever having used cannabis, 35.9%reported using cannabis in the past year, and 22.2%reported using cannabis in the past 30 days.3 While most youth subsequently discontinue use, a small but appreciable subset continue using cannabis products and progress to higher levels of use; in 2018, 5.9%of students in 12th grade reported daily use of cannabis products.3 The period following experimentation represents a critical juncture during which youth decide to continue or discontinue use of cannabis products.5,6 The type of cannabis product used may influence subsequent cannabis use patterns following experimentation owing to differential drug delivery mechanisms and variation in the sensory effects associated with the use of different products. Each cannabis product is available in different formulations with varying levels of THC, elicits different sensory effects because of the method of administration (ie, smoking vs eating vs vaping) and the additives present in the product (ie, flavors in edible and vaping products),7-9 has different pharmacokinetics of drug absorption,10 and varies in adolescents’ ability to access that product and use it without consequence (eg, some methods are easier to conceal).4,11-13 If certain cannabis products are more reinforcing (ie, leading to dependent use patterns), result in more positive sensory effects, or are more accessible to obtain and use, those cannabis products may pose a greater risk of continued use and warrant a public health response targeting those specific cannabis products.

However, whether the potential for abuse differs among products is unknown. In the current study,we examined the association of cannabis use at baseline with persistent (ie, continued) cannabis use and progression to more frequent cannabis use (ie, increase in the number of days of use) over 1 year of follow-up for 5 different cannabis products (ie, combustible cannabis, blunts, vaporized cannabis, cannabis edibles, and cannabis concentrate) in a prospective cohort of adolescents in southern California. Our primary aim was to determine whether the strength of these associations (ie, the risk of persistent use or progression of use) differed by the type of cannabis product used.

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