High-potency cannabis use linked to poorer health outcomes

A systematic review has noted findings within the “problem” cannabis use domain that suggest an association with high-potency use.

“High-potency cannabis is a major topic in contemporary cannabis policy discussions” amidst a persistent rise in concentrations of delta-9-tetrahydrocannabinol (THC) in cannabis (ie, potency), according to the investigators. However, its effect on health is not yet fully understood.

To address this gap, the investigators obtained records from a systematic search of five biochemical research databases and developed ecologically relevant potency (percent THC) exposure-comparison categories (1 percent to 9 percent, 10 percent to 19 percent, 20 percent to 30 percent, kief/resin [∼30 percent to 50 percent], concentrates [≥60 percent). A scientific report was used to determine eligibility.

Two reviewers performed article screening and selection, extraction, and quality assessment separately. The findings were synthesized using quantitative (association direction, binomial test) and narrative approaches. The investigators assessed certainty in the evidence using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework.

Forty-two studies out of 4,545 screened records met the eligibility criteria. Most research focused on outcomes in the domains of mental health, problem cannabis use, and other substance use.

Findings seen in the problem cannabis use domain suggested a link with the use of higher-potency cannabis. On the other hand, less consistent findings were noted in other domains, but these appeared to favour poorer outcomes with higher-potency use. Therapeutic outcomes were mixed and limited.

Notably, there was “very low” certainty in the evidence overall.

“Research is largely limited to cross-sectional studies spanning few adverse health domains, underscoring the need for prospective studies probing therapeutic, cardiorespiratory, cancer, and pre- and perinatal outcomes,” the investigators said. “Policies to curb high-potency cannabis use may be warranted while the evidence base improves.”