Self-reported THC content and associations with perceptions of feeling high among cannabis consumers

Few studies have examined consumer knowledge and communication of tetrahydrocannabinol (THC) content among cannabis consumers, including potential differences by cannabis legislation. The study sought to: (i) examine self-reported knowledge of THC content across 10 cannabis products; (ii) examine self-reported intoxication levels; and (iii) examine association between self-reported THC levels and intoxication levels.

Repeat cross-sectional surveys were conducted in Canada and the United States in September-November 2020 as part of the International Cannabis Policy Study. Respondents were past 12-month cannabis consumers, aged 16-65 (n = 13,689). A weighted logistic regression model examined the association between expected intoxication of dried flower, jurisdiction and frequency of cannabis use.

Across all 10 cannabis products, approximately two-thirds of consumers did not know the quantitative THC level of the cannabis product they last used. Qualitative levels of THC (e.g., 'low' or 'high' THC) showed moderate correspondence with quantitative self-reported THC levels for most products. Approximately half of consumers across all products reported achieving their desired intoxication level at last use, with higher levels among more frequent consumers and Canadian consumers of dried flower (F = 2.54, p = 0.019).

Overall, comprehension of THC levels in cannabis products is low among consumers in both illegal and legal markets.