Advancing research on cannabis: Dose response and growing concerns

APA partnered with the College on Problems of Drug Dependence (CPDD) to comment on two important cannabis research issues:

• Developing a standard unit dose of tetrahydrocannabinol (THC).
• Expanding the range of cannabis products available for research.

APA and CPDD responded (PDF, 148KB) to a Request for Information from the National Institute on Drug Abuse (NIDA) and supported a recommendation from its Cannabis Policy Research Working Group (PDF, 969KB) to “explore the possibility of constructing a standardized dose similar to that for alcohol (the standard drink), tobacco (a cigarette), or opioids (morphine milligram equivalents) for researchers to employ in analyzing use and for users to understand their consumption.” NIDA recommended setting the standard at 5 milligrams. APA’s comments noted that a standard unit dose of THC, accurately labeled on products, would significantly enhance the ability to quantify cannabis use/exposure in individual study participants and patients, and to interpret and compare results across research studies. Establishing a standardized unit dose for THC would also help research participants and other consumers by improving the accuracy of their self-reported cannabis use and helping prevent adverse events related to overconsumption of retail cannabis products. However, APA also raised four concerns about variability:

• THC concentration varies widely across the range of available cannabis products.
• Individual patterns of consumption of bulk product vary with no set “serving size.”
• Circulating THC levels depend on whether cannabis is smoked, vaped, or ingested.
• Analytical testing and labeling requirements may be more important than the unit dose.

APA and CPDD responded (PDF, 320KB) to a Notice of Proposed Rule Making (NPRM) from the Drug Enforcement Administration (DEA) setting forth regulations to expand the availability of cannabis products manufactured for research. NIDA has been the sole source for cannabis grown and processed for research for the last 50 years. The new rules will govern who can grow and process cannabis and how the cannabis will be stored and sold. DEA has received approximately three dozen applications but estimates it will only approve three to 15. Many of the applicants may be producing cannabis for their own research, and APA expressed concern that the market for NIH-funded cannabis research is very small (40 scientists by DEA’s estimate) and unlikely to increase as long as the DEA maintains its complex regulatory framework for conducting that research. In order to keep pace with patterns of real-world cannabis use, the research community needs access to the same range of products that consumers can buy from local dispensaries in the 33 states (and the District of Columbia) that sell medicinal or recreational cannabis. However, one of DEA’s evaluation criteria would likely disqualify existing manufacturers from participating in the new federal grower program because although they comply with state laws, they violate the federal Controlled Substances Act.

APA and CPDD detailed several additional actions needed to facilitate cannabis research including decreasing security requirements for cannabis storage and eliminating DEA scientific protocol review, which is redundant with that of the Food and Drug Administration.