Subjective effects of combustible, vaporized, and edible cannabis: Results from a survey of adolescent cannabis users

Background: Data from controlled laboratory experiments in adults indicate that the subjective effects of cannabis vary by administration method (e.g., combustible, vaporized). Whether the subjective effects of cannabis experienced in the natural ecology and among adolescents differ by cannabis administration method is unknown. In this observational study, adolescents' retrospective reports of subjective effects after combustible, edible, and vaporized cannabis use were examined. Methods: Students from ten public schools in Los Angeles, CA, USA (M[SD] age = 16.1 [.43] years) who reported past 6-month use of combustible, edible, or vaporized cannabis (N = 584) were surveyed on subjective effects experienced after use (yes/no). They were provided with a 12 item self-report checklist of six positive (e.g., relaxed, energetic) and six negative (e.g., drowsy, lazy) subjective effects. For each method of administration, affirmative responses were summed in positive (range: 0-6) and negative (range: 0-6) effect composite scores. Results: Generalized estimating equations adjusted for demographics and recent cannabis use revealed a graded pattern of differences in positive subjective effects across products, with highest scores for combustible (M [SD] = 3.98[1.76]), followed by edible (M[SD] = 3.58 [2.04]) and vaporized (M[SD] = 3.11 [2.21]) cannabis (all pairwise cross-product contrasts p < .01). Mean negative effect score was highest for edible (M[SD] = 2.27 [1.95]), followed by combustible (M[SD] = 1.94 [1.66]), and vaporized (M[SD] = 1.34 [1.73]) cannabis, respectively (all pairwise contrasts p < .02). Conclusion: Adolescents' reports of subjective effects varied across cannabis administration methods. Combustible cannabis' more desirable subjective effects profile might be indicative of higher abuse liability.