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Randomized Controlled Trial
. 2018 Nov 2;1(7):e184841.
doi: 10.1001/jamanetworkopen.2018.4841.

Acute Effects of Smoked and Vaporized Cannabis in Healthy Adults Who Infrequently Use Cannabis: A Crossover Trial

Tory R Spindle  1 , Edward J Cone  1 , Nicolas J Schlienz  1 , John M Mitchell  2 , George E Bigelow  1 , Ronald Flegel  3 , Eugene Hayes  3 , Ryan Vandrey  1
Affiliations
Randomized Controlled Trial

Acute Effects of Smoked and Vaporized Cannabis in Healthy Adults Who Infrequently Use Cannabis: A Crossover Trial

Tory R Spindle et al. JAMA Netw Open. .

Erratum in

  • Error in Table Title.
    [No authors listed] [No authors listed] JAMA Netw Open. 2018 Dec 7;1(8):e187241. doi: 10.1001/jamanetworkopen.2018.7241. JAMA Netw Open. 2018. PMID: 30646302 Free PMC article. No abstract available.

Abstract

Importance: Vaporization is an increasingly popular method for cannabis administration, and policy changes have increased adult access to cannabis drastically. Controlled examinations of cannabis vaporization among adults with infrequent current cannabis use patterns (>30 days since last use) are needed.

Objective: To evaluate the acute dose effects of smoked and vaporized cannabis using controlled administration methods.

Design, setting, and participants: This within-participant, double-blind, crossover study was conducted from June 2016 to January 2017 at the Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, and included 17 healthy adults. Six smoked and vaporized outpatient experimental sessions (1-week washout between sessions) were completed in clusters (order counterbalanced across participants); dose order was randomized within each cluster.

Interventions: Cannabis containing Δ9-tetrahydrocannabinol (THC) doses of 0 mg, 10 mg, and 25 mg was vaporized and smoked by each participant.

Main outcomes and measures: Change from baseline scores for subjective drug effects, cognitive and psychomotor performance, vital signs, and blood THC concentration.

Results: The sample included 17 healthy adults (mean [SD] age, 27.3 [5.7] years; 9 men and 8 women) with no cannabis use in the prior month (mean [SD] days since last cannabis use, 398 [437] days). Inhalation of cannabis containing 10 mg of THC produced discriminative drug effects (mean [SD] ratings on a 100-point visual analog scale, smoked: 46 [26]; vaporized: 69 [26]) and modest impairment of cognitive functioning. The 25-mg dose produced significant drug effects (mean [SD] ratings, smoked: 66 [29]; vaporized: 78 [24]), increased incidence of adverse effects, and pronounced impairment of cognitive and psychomotor ability (eg, significant decreased task performance compared with placebo in vaporized conditions). Vaporized cannabis resulted in qualitatively stronger drug effects for most pharmacodynamic outcomes and higher peak concentrations of THC in blood, compared with equal doses of smoked cannabis (25-mg dose: smoked, 10.2 ng/mL; vaporized, 14.4 ng/mL). Blood THC concentrations and heart rate peaked within 30 minutes after cannabis administration and returned to baseline within 3 to 4 hours. Several subjective drug effects and observed cognitive and psychomotor impairments persisted for up to 6 hours on average.

Conclusions and relevance: Vaporized and smoked cannabis produced dose-orderly drug effects, which were stronger when vaporized. These data can inform regulatory and clinical decisions surrounding the use of cannabis among adults with little or no prior cannabis exposure.

Trial registration: ClinicalTrials.gov Identifier: NCT03676166.

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Vandrey reported receiving personal fees and has served as a consultant or received honoraria from Zynerba Pharmaceuticals, Insys Therapeutics, Battelle Memorial Institute, and Canopy Health Innovations Inc outside the submitted work. Drs Vandrey and Spindle reported receiving grants from the Substance Abuse and Mental Health Services Administration (SAMHSA) during the conduct of the study. Dr Cone reported serving as a consultant for ConeChem Research, LLC and RTI during the conduct of the study. Dr Schlienz reported grants from the National Institute on Drug Abuse outside the submitted work. Dr Mitchell reported grants from SAMHSA during the conduct of the study. Dr Hayes reported receiving funding from the Department of Health and Human Services, SAMHSA, National Laboratory Certification Program, and RTI International during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.
Figure 1.. CONSORT Flow Diagram
THC indicates Δ9-tetrahydrocannabinol.
Figure 2.
Figure 2.. Mean Ratings for Visual Analog Scale (VAS) Item Drug Effect From the Drug Effect Questionnaire Displayed Over Time and Across Δ9-Tetrahydrocannabinol Dose for Smoked and Vaporized Conditions
Scores ranged from 0 (not at all) to 100 (extremely). Error bars indicate SEM. Horizontal axes are not accurate time scales and represent the time points at which subjective drug effects were assessed. BL indicates baseline time point; and Δ, difference or change.
Figure 3.
Figure 3.. Mean Change From Baseline Scores for Average Distance From Central Stimulus From Divided Attention Task, Total Correct on Digit Symbol Substitution Task, and Total Correct on Paced Auditory Serial Addition Task
A and B, Higher scores indicate poorer performance relative to baseline. C-F, Lower scores indicate worse performance relative to baseline. Error bars indicate SEM. All scores are shown over time and are displayed by Δ9-tetrahydrocannabinol dose and inhalation method. Horizontal axes are not accurate time scales and represent the time points at which cognitive and psychomotor performance was measured. BL indicates baseline time point; and Δ, difference or change.
Figure 4.
Figure 4.. Mean Change From Baseline Score for Heart Rate Over Time, Displayed by Δ9-Tetrahydrocannabinol Dose for Smoked and Vaporized Conditions
Error bars indicate SEM. Horizontal axes are not accurate time scales and represent the time points at which heart rate was measured. BL indicates baseline time point; bpm, beats per minute; and Δ, difference or change.
See this image and copyright information in PMC

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