A naturalistic study of orally administered vs. inhaled legal market cannabis: cannabinoids exposure, intoxication, and impairment

Abstract

Rationale: Published studies examining the effects of cannabis have largely utilized forms of cannabis that are not representative of the legal market products currently available.

Objectives: The present study aimed to characterize naturalistic use of legal market flower and edible products by examining associations among blood cannabinoids and amount of THC consumed as well as physiological, cognitive, and subjective effects in users of edible and flower forms.

Method: Eighty-four participants who used cannabis at least 1 × /week (55 flower cannabis using participants; 29 edible cannabis using participants mean age = 31.95 years, 44% female) participated. At the experimental appointment in our mobile laboratory, participants completed a blood draw to assess plasma cannabinoids, measures of heart rate, subjective drug effects, and cognition both before and after ad libitum use of legal market flower or edible cannabis.

Results: Average self-reported THC consumed was 15.97 mg (SD = 22.40) in edible users and 51.25 mg (SD = 45.23) in flower users. In the edible group, but not the flower group, strong correlations emerged between self-reported ad libitum THC consumed and plasma THC. Plasma THC was significantly higher after use of inhaled cannabis, but similar levels of plasma THC metabolites and similar levels of subjective intoxication and verbal memory impairment were observed in both flower and edible users.

Conclusions: Findings support strong correlations among ad libitum THC consumed and THC plasma levels after edible cannabis use and suggest few differences in intoxication and impairment between edible and flower cannabis users after ad libitum use. This novel study provides important preliminary data on the pharmacology and effects of legal market edible cannabis.

Keywords: CBD; Cannabinoids; Drug reward; Edibles; Marijuana; THC.

Fig. 1

Scatter plot of ad Libitum THC dose and THC plasma concentrations after naturalistic edible vs. flower use. a Correlations among ad libitum THC dose (mg) and THC plasma levels (ng/mL) 1-h post-use in edible users. b Correlations among ad libitum THC dose (mg) and THC plasma levels immediately post-use (ng/mL) in flower users. Results show a strong linear relationship among ad libitum THC dose and THC plasma levels in the edible group (r = 0.83) and no linear relationship among ad libitum THC dose and THC plasma in flower users (r = 0.15)

Fig. 2

Cannabinoid plasma concentrations before and after naturalistic edible vs. flower use. a Changes in blood THC (nanograms per milliliter (ng/mL)) before cannabis use (pre-use) and immediately after cannabis use (post-use) (pre-use median = 0.88, range = 0–52.51; post-use median = 44.81, range = 0–993). b Changes in blood THC metabolite COOH-THC (ng/mL) before cannabis use and immediately after cannabis use (pre-use median = 12.98, range = 0–574.549; post-use median = 24.74, range = 0–392.04). c Changes in blood THC metabolite 11-OH-THC (ng/mL) before cannabis use and immediately after cannabis use (pre-use median = 0, range = 0–21.075; post-use median = 2.68, range = 0–24.242). d Changes in blood CBD (ng/mL) before cannabis use (pre-use) and immediately after cannabis use (post-use) (pre-use median = 0, range = 0–2.061; post-use median = 0.42, range = 0–22.97). Orange lines indicate the edible group and blue lines indicate the flower group. Across both forms of cannabis, THC, 11-OH-THC, and CBD were elevated after cannabis administration. The flower group had higher levels and a stronger linear effect of THC after cannabis administration (i.e., a higher peak at the post use assessment). The edible group had higher levels of CBD across both assessments, as well as a stronger linear effect after cannabis administration (i.e., a higher peak at the post use assessment)

Fig. 3

Heart rate before and after naturalistic edible vs. flower use. Changes in heart rate before cannabis use (pre-use), immediately after cannabis use (post-use) (pre-use median = 72, range = 52–108; post-use median = 87, range = 54–128). Orange lines indicate the edible group, and blue lines indicate the flower group. Across both forms of cannabis, heart rate was elevated after cannabis administration. There was a significant group × time interaction, such that flower group had a higher heart rate after cannabis administration (i.e., a higher peak at the post-use assessment)

Fig. 4

Subjective drug effects before and after naturalistic edible vs. flower use. a Changes in self-reported positive mood (POMS Elation subscale) before cannabis use (pre-use) and immediately after cannabis use (post-use) (pre-use median = 5, range = 0–16; post-use median = 7, range = 0–16). b Changes in self-reported tension (Profile of Mood States (POMS) Tension subscale) before cannabis use (pre-use) and immediately after cannabis use (post-use) (preuse median = 1, range = 0–11; post-use median = 1, range = 0–13). c Changes in self-reported paranoid (single measure POMS Paranoid) before cannabis use (pre-use) and immediately after cannabis use (post-use) (pre-use median = 0, range = 0–1; post-use median = 0, range = 0–4). d Changes in the ARCI-marijuana scale before cannabis use and immediately after cannabis use (post-use) (pre-use median = 2, range = 0–8; post-use median = 6, range = 2–12). Orange lines indicate the edible group, and blue lines indicate the flower group. POMS Elation, POMS Tension, POMS Paranoid, and ARCI were elevated after cannabis administration. The flower group reported a greater positive mood (POMS Elation) overall, but across all other measures, there were no difference between edible and flower groups. Further, no group × time interactions were present suggesting no differential effects of product type on subjective drug or mood effects after use of flower vs. edible products