THC Consumption Limits Clarify Cannabis Use Disorder Risk
New research defines weekly THC intake levels linked to cannabis use disorder in adults and adolescents, offering a practical framework for safer use discussions.
A UK study suggests that regularly consuming more than about 40 mg of THC per week for adults and 30 mg per week for adolescents is associated with a higher risk of developing cannabis use disorder, supporting the use of standardized THC units in clinical care.
Study Details
Cannabis use disorder affects roughly one in five people who use cannabis and can lead to significant distress or impairment. Despite rising cannabis availability, clinicians have lacked clear, evidence-based thresholds to help patients understand risk.
Researchers from the University of Bath analyzed data from the CannTeen observational study to identify weekly THC intake levels associated with increased risk for cannabis use disorder. The work builds on earlier efforts, including guidance from the National Institutes of Health, to define a standard THC unit as 5 mg of THC, similar to standard alcohol units.
The findings were published in the journal Addiction.
Methodology
The study included adults aged 26 to 29 years and adolescents aged 16 to 17 years in London who reported cannabis use during a one-year period. Researchers estimated average weekly THC intake using detailed self-reports that accounted for frequency, quantity, and potency of cannabis products.
Cannabis use disorder diagnoses were determined using DSM-5 criteria. Statistical models assessed how well weekly THC units could distinguish between no disorder, any disorder, and moderate to severe disorder.
Key Findings
Adults consuming more than about 8.3 THC units per week, roughly 41 mg of THC, showed higher risk for any cannabis use disorder
Adolescents exceeded risk thresholds at lower levels, around 6.0 THC units per week or about 30 mg of THC
Higher weekly intake was associated with moderate to severe cannabis use disorder, especially in adolescents
Standard THC units demonstrated strong accuracy in identifying risk across age groups
Implications for Practice
For patients, these findings suggest that cannabis-related harm can occur at levels many regular users may consider modest. Framing consumption in simple THC units may help individuals better understand their exposure and make informed choices.
For healthcare providers, standardized THC units offer a practical tool for screening, counseling, and tracking cannabis use over time. Similar to alcohol guidelines, lower-risk cannabis use recommendations could be developed, with particular caution for adolescents who appear more vulnerable at lower doses.
While cannabis contains many active compounds beyond THC, this approach provides a starting point for clearer, more consistent conversations in both clinical and public health settings.