Acute Effects of Smoked and Vaporized Cannabis in Healthy Adults Who Infrequently Use Cannabis A Crossover Trial.
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. To evaluate the acute dose effects of smoked and vaporized cannabis using controlled administration methods. 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. Cannabis containing Δ9-tetrahydrocannabinol (THC) doses of 0 mg, 10 mg, and 25 mg was vaporized and smoked by each participant. Change from baseline scores for subjective drug effects, cognitive and psychomotor performance, vital signs, and blood THC concentration. 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 ngmL vaporized, 14.4 ngmL). 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. 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. ClinicalTrials.gov Identifier NCT03676166.