Association of Naturalistic Administration of Cannabis Flower and Concentrates With Intoxication and Impairment.
The rapidly growing legal cannabis market includes new and highly potent products, the effects of which, to our knowledge, have not previously been examined in biobehavioral research studies because of federal restrictions on cannabis research. To use federally compatible, observational methods to study high-∆9-tetrahydrocannabinol (THC) legal market forms of cannabis. In this cohort study with a between-groups design that was conducted in a community and university setting, cannabis flower users and concentrate users were randomly assigned to higher- vs lower-THC products within user groups. Participants completed a baseline and an experimental mobile laboratory assessment that included 3 points before, immediately after, and 1 hour after ad libitum legal market flower and concentrate use. Of the 133 individuals enrolled and assessed, 55 regular flower cannabis users (41.4%) and 66 regular concentrate cannabis users (49.6%) complied with the studys cannabis use instructions and had complete data across primary outcomes. Flower users were randomly assigned to use either 16% or 24% THC flower and concentrate users were randomly assigned to use either 70% or 90% THC concentrate that they purchased from a dispensary. Primary outcome measures included plasma cannabinoids, subjective drug intoxication, and neurobehavioral tasks testing attention, memory, inhibitory control, and balance. A total of 121 participants completed the study for analysis 55 flower users (mean SD age, 28.8 8.1 years 25 women 46%) and 66 concentrate users (mean SD age, 28.3 10.4 years 30 women 45%). Concentrate users compared with flower users exhibited higher plasma THC levels and 11-hydroxyΔ9-THC (THCs active metabolite) across all points. After ad libitum cannabis administration, mean plasma THC levels were 0.32 (SE 0.43) μgmL in concentrate users (to convert to millimoles per liter, multiply by 3.18) and 0.14 (SE 0.16) μgmL in flower users. Most neurobehavioral measures were not altered by short-term cannabis consumption. However, delayed verbal memory (F1,203 32.31 P < .001) and balance function (F1,203 18.88 P < .001) were impaired after use. Differing outcomes for the type of product (flower vs concentrate) or potency within products were not observed. This study provides information about the association of pharmacological and neurobehavioral outcomes with legal market cannabis. Short-term use of concentrates was associated with higher levels of THC exposure. Across forms of cannabis and potencies, users domains of verbal memory and proprioception-focused postural stability were primarily associated with THC administration.