Marijuana practices and patterns of use among young adult medical marijuana patients and non-patient marijuana users

Highlights

• Non-patient marijuana users (NPU) report using marijuana diverted from dispensaries.

• Young adult medical marijuana patients (MMP) use more marijuana than young NPU.

• Over half of sample report current use of concentrates, e.g., oil, dab, wax.

• Vaporization of concentrates and marijuana was more common among MMP than NPU.

• Trend toward less current misuse of prescription drugs among MMP compared to NPU.

Abstract

Background

Little is known about young adult medical marijuana patients (MMP) and their marijuana using patterns and practices, which includes frequency of use, sourcing of marijuana products, forms/modes of administration, and patterns of illicit/prescription drug misuse, compared to non-patient marijuana users (NPU).

Methods

Young adults (N = 366) aged 18–26 years old were sampled in Los Angeles in 2014–15 and segmented into NPU (n = 156), marijuana users who never had a medical marijuana (MM) recommendation, and MMP (n = 210), marijuana users with a current, verified MM recommendation. Differences regarding self-reported marijuana and other drug use during the past 90 days are expressed as unadjusted risk ratios or differences in means.

Results

MMP reported significantly greater mean days of use (76.4 vs. 59.2, p < 0.001) and mean dollars spent on marijuana products (564.5 vs. 266.9, p < 0.001) than NPU. Approximately one-quarter (22.6%) of both MMP and NPU report selling marijuana obtained from a dispensary to someone else in the past 90 days. MMP were more likely to report vaporization modalities for concentrates (URR = 1.5, 95% C.I. = 1.2, 2.0) and for marijuana (URR = 1.5, 95% C.I. = 1.1, 2.1) than NPU. Though not significant, trends toward lower misuse of prescription drugs in the past 90 days were observed among MMP compared to NPU.

Conclusion

MMP reported greater access to marijuana via dispensaries, more frequent and intensive use of marijuana, and greater use of non-combustible forms of marijuana compared to NPU. MMP reported less recent misuse of prescription drugs compared to NPU.

Introduction

Young adults, who have the highest rate of marijuana use among all age groups in the U.S. (Center for Behavioral Health Statistics and Quality, 2015), are an important population to study as drug policies evolve towards legalizing marijuana for medical and recreational use. In 21 states where marijuana has been legalized for medical use only (excluding Alaska, Colorado, Oregon, Washington, and the District of Columbia), two groups of young adult marijuana users now exist: medical marijuana patients (MMP) − persons possessing a doctor’s recommendation which enables legal access to medical marijuana at dispensaries; and non-patient users (NPU) − persons who use marijuana without possessing a doctor’s recommendation or legal access, i.e., illicit users. While studies of older MMP and NPU consistently indicate more frequent marijuana use among MMP (Richmond et al., 2015, Woodruff and Shillington, 2016), no studies have compared specific patterns and practices of marijuana use among young adult MMP and NPU, which have important implications for assessing legalization policies and health among young adults.

California, which was the first state to legalize the use of marijuana for medical purposes in 1996 following the passage of Proposition 215, has one of the broadest definitions of health conditions for which a physician can recommend medical marijuana (Wilkinson et al., 2016). Among Californians, 9.2% of young adults (aged 18 to 24 years old) report having “ever used medical marijuana” in 2012, which is the highest rate among any age group and nearly double the state average of 5.2% (Ryan-Ibarra et al., 2014). Including non-medical use, 21.5% of young adults in California reported any marijuana use in the past month in 2014, which is the highest rate of any age group and more than twice the state average of 9.2% (CBHSQ, 2015). Apart from lifetime medical marijuana use (Ryan-Ibarra et al., 2014), data are limited regarding frequency and quantity of marijuana use among young adult MMP. Studies of older samples of MMP recruited from California dispensaries indicate that most are daily marijuana users (Bonn-Miller et al., 2014, Grella et al., 2014) and 6 to 12 g was the average weekly consumption (Bonn-Miller et al., 2014). Given this history, California offers an important setting to examine differences between frequencies of marijuana use among young adult MMP and NPU.

The common understanding of forms and modes of administering marijuana has traditionally been based upon reports by NPU or illicit users but is increasingly informed by MMP and other legal users. Conventionally, NPU smoked dried marijuana leaves/buds using some kind of pipe (including a water pipe or bong) or rolled marijuana with paper or a cigar wrapper to form a joint or blunt (Kelly, 2005, Sifaneck et al., 2005). Vaporization, which heats marijuana leaves (Gieringer, 2001) or marijuana “concentrates” (Raber et al., 2015) to the point where cannabinoids are released without combustion, has become increasingly common in states where marijuana is legal for recreational or medical use (Daniulaityte et al., 2015, Pacula et al., 2016). Examples of concentrates include “dabs” and “oil,” which are high potency forms created through an extraction process (Raber et al., 2015). Dabs (solid form) can be vaporized using an “oil rig,” which is similar to a bong for smoking marijuana leaves (Black, 2013), whereas oil (liquid form) is commonly vaporized using a battery-powered device similar to an e-cigarette (Budney et al., 2015). Forms of marijuana consumed orally, such as food products, tinctures (alcohol and marijuana), and beverages, are also commonly reported among both NPU (Murphy et al., 2015) and MMP (Grella et al., 2014, Murphy et al., 2015). Among adults, conventional modes of administering marijuana, i.e., smoking, however, remain more typical than alternative modes, i.e., vaporization, oral (Pacula et al., 2016, Schauer et al., 2016). Overall, little is known as to how marijuana practices differ between young or older MMP and NPU (Richmond et al., 2015, Woodruff and Shillington, 2016).

Epidemiological surveys provide limited information on where young adult NPU obtain marijuana (Harrison et al., 2007) or the types/forms of marijuana consumed for personal use. In contrast, qualitative research has shown that high potency “designer” strains, such as Jack Herer, were sold to NPU via delivery services in New York (Sifaneck et al., 2007), and from medical marijuana dispensaries in Los Angeles and elsewhere (Murphy et al., 2015). No research has examined the issue of marijuana sources among young adult or older MMP and NPU, or which sources each group may prefer (Murphy et al., 2015, Richmond et al., 2015, Woodruff and Shillington, 2016).

Apart from marijuana, young adults also have the highest rates of recent other drug use among any age group, including opioids, hallucinogens, stimulants, and sedatives (CBHSQ, 2015). While other studies of older MMP and NPU report mixed findings on other recent drug use among MMP, i.e., lower (Richmond et al., 2015), or higher (Woodruff and Shillington, 2016), no studies have examined rates of other drug use among young adult MMP in comparison to NPU, which may provide insights into potential substitution effects offered by medical marijuana (Mikuriya, 2004, Murphy et al., 2015; Reiman, 2009).

Given generally high rates of non-medical marijuana and other drug use among young adults and a lack of research specifically examining use among young adult MMP, a descriptive analysis was undertaken to characterize and compare young adult MMP and NPU in Los Angeles, California in the following domains: frequencies and quantity of marijuana use; forms/modes of administering marijuana; sources of marijuana; and rates of other drug use. An overarching hypothesis is that young adult MMP, who have legal access to marijuana via dispensaries, will use more marijuana (including greater diversity of forms and modes) and fewer other drugs than NPU.