Influence of cannabis potency on mental health outcomes among adolescents and young adults: scoping review

Background: Recently, there has been a significant rise in potency (% tetrahydrocannabinol (THC)) of cannabis products globally. As such, there is a need for a better understanding of the relationship between cannabis potency and mental health outcomes, especially in a developmentally vulnerable population such as adolescents and young adults.

Aims: The objective of this scoping review was to summarise existing literature investigating the potency of cannabis products as it relates to mental health outcomes in adolescents and young adults aged 14–25.

Method: Systematic searches of MEDLINE, Embase, CINAHL and PsycINFO were conducted for relevant manuscripts up to October 2025. Following PRISMA-ScR guidelines, retrieved studies were then screened and data extracted by two independent reviewers.

Results: Out of 11 225 studies identified by our searches, 71 were included in the review after screening. Compared with low-potency cannabis, our findings suggest that high-potency cannabis is more strongly associated with severe mental health issues, such as cannabis dependence, psychosis and cognitive deficits.

Conclusions: Overall, it was found that high-potency cannabis use (>15% THC) was associated with a great number and magnitude of adverse mental health outcomes. As such, the potency of cannabis products should be measured in future cannabis research that investigates short- and long-term outcomes. Additionally, the potency of cannabis products should be a consideration in any future cannabis regulatory policy discussions.