Delta-8 tetrahydrocannabinol: a scoping review and commentary

Background and Aims: Delta-8 tetrahydrocannabinol (THC) is a psychoactive substance from the Cannabis plant that has been rising in popularity in the United States since the 2018 US Farm Bill implicitly legalized it. This study reviewed research from peer-reviewed and non-peer-reviewed (e.g. anecdotal and news) reports related to delta-8 THC to summarize current knowledge and implications for public health and safety. Methods: A scoping review was conducted using PubMed, Scopus, Google Scholar and Google as search engines, leading to the identification of 103 documents that were summarized. The themes that emerged were (1) legality, (2) use (popularity, motives, psychoactivity/potency, benefits/consequences), (3) synthesis (byproducts, laboratory testing) and (4) retail (availability, price, packaging, youth-oriented marketing). A second author independently coded 20% of the documents, which verified the categorization of articles by these emergent themes. Results: Most research used animal/cell models or focused upon ways to identify the chemical structure of delta-8 THC in various products. Findings suggest that people often use delta-8 THC as a substitute for other substances. Anecdotally, delta-8 THC is a less potent psychoactive than delta-9 THC; however, several negative consequences have been reported. There is no federal age restriction for purchase/possession of delta-8 THC products. Delta-8 THC is readily accessible on-line, is typically less expensive than delta-9 THC and is often marketed in ways that would seemingly appeal to children. There are no regulations on synthesis, resulting in products being contaminated and/or yielding inconsistent effects. There have been thousands of calls to US poison control centers due to accidental delta-8 THC exposure among minors. Conclusions: Most research on delta-8 THC is largely anecdotal, not peer-reviewed and does not involve human subjects. Future research should examine delta-8 THC use using nationally representative samples to more clearly understand the prevalence and consequences of use. Laws are needed to mitigate the risks of using delta-8 THC, particularly quality control of synthesis and minimum purchase age.