The following is a summary of “High-Potency Cannabis Use and Health: A Systematic Review of Observational and Experimental Studies,” published in the March 2025 issue of American Journal of Psychiatry by Lake et al. 

Rising delta-9-tetrahydrocannabinol (THC) levels in cannabis have made high potency use a key policy concern. Its health impact remains unclear. 

Researchers conducted a retrospective study reviewing observational and experimental studies on high-potency cannabis use and health outcomes. 

They obtained records from five biomedical databases and categorized THC potency (1%–9%, 10%–19%, 20%–30%, kief/resin ∼30%–50%, concentrates ≥60%). A landmark report determined outcome eligibility. About 2 reviewers independently screened, selected, extracted, and assessed quality. Findings were synthesized using quantitative and narrative methods, with certainty assessed via Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). 

The results showed that of 4,545 screened records, 42 were eligible. Most studies focused on mental health, “problem” cannabis use, and other substance use. Higher-potency cannabis was linked to “problem” use, while there outcomes were inconsistent but leaned toward poorer effects. Therapeutic findings were limited and mixed. Overall, evidence certainty was “very low.” 

Investigators found a possible link between high-potency cannabis and “problem” use. Research was limited, highlighting the need for prospective studies on various health outcomes. 

Source: psychiatryonline.org/doi/10.1176/appi.ajp.20240269