Using ecological momentary assessment to quantify Δ-9-tetrahydrocannabinol and cannabidiol use across different forms of cannabis: Feasibility in a sample of Canadian young adults reporting frequent cannabis use.

AIMS: To establish the feasibility of using ecological momentary assessment (EMA) to estimate total quantities of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) used across different forms of cannabis, and to assess the predictive validity of THC estimates for predicting acute cannabis-related consequences.

DESIGN

14-day EMA using a smartphone application to assess cannabis use in real time.

SETTING

Canada.

PARTICIPANTS

Targeted sample of n = 42 young adults (59.52% women, mean age 25 years) reporting frequent cannabis use.

MEASUREMENTS: Surveys completed immediately prior to cannabis use assessed the quantities, THC content and CBD content of various forms of cannabis to be used in the current session; participants also uploaded photos of the cannabis product labels when available. Surveys administered at fixed times throughout the day (84.81% completion rate) assessed acute cannabis-related consequences.

FINDINGS: Participants completed a total of 786 pre-cannabis surveys, of which 79.39% and 77.35% contained sufficient information to calculate total THC and CBD (in milligrams), respectively. High agreement was observed between participant-entered THC and CBD contents and those shown in corresponding photos of cannabis product labels. Aggregating across all products used, participants reported using an average of 141.41 [standard deviation (SD) = 224.62, range = 0.00-2000.00] milligrams of THC (i.e. 28.28 standard five-milligram units) and 7.53 (SD = 34.87, range = 0.00-484.22) milligrams of CBD per day. Multilevel models revealed that participants were more likely to report acute negative consequences following sessions when their estimated THC use was higher than their typical THC use. At the between-person level, participants reporting more THC use on average across sessions were less likely to report negative consequences overall.

CONCLUSIONS

Using ecological momentary assessment to estimate total quantities of Δ-9-tetrahydrocannabinol and cannabidiol used across different forms of cannabis appears to be feasible, with preliminary predictive validity for acute negative cannabis-related consequences.