The CBD Cannabis-Use Trial Required Participants to Smoke Cannabis With Tobacco
The CBD cannabis-use-disorder trial studied people who reported combining cannabis with tobacco. Its treatment results therefore did not come from a cannabis-only population.
Tobacco use was an entry condition
The investigators required participants to report co-administering their cannabis with tobacco, alongside a desire to stop cannabis use and at least one unsuccessful quit attempt. This was not simply an incidental tobacco imbalance discovered after randomization. It defined the population from which the treatment groups were recruited.
The study measured both substances
Cannabis outcomes included self-reported abstinent days and urinary THC-COOH adjusted for creatinine. Tobacco outcomes included cigarette reports and urinary cotinine adjusted for creatinine. These were different analytes and behavioral measures. A cannabis-use change should not be substituted for a measured nicotine-use change, or vice versa.
Generalization requires the original population
Randomization supports a CBD-versus-placebo comparison within this selected trial. It does not establish an identical effect among people who only vape cannabis, use oral products or never use tobacco. Co-use also supplies a reason to examine both behaviors during cessation. The trial found promising cannabis-use signals at selected CBD doses with psychological support, but it was not a direct comparison of treatment response in cannabis-only users versus tobacco co-users.
Related analysis: the trial’s main results and limitations.
