UK researchers have discovered a link between cannabis potency, addiction and mental health problems that could help inform how the substance is regulated around the world.
A team from the University of Bath’s Addiction and Mental Health Group analysed 20 studies involving almost 120,000 people.
They found people using high-THC cannabis are more likely to experience addiction or a psychotic disorder such as schizophrenia than those using low-THC products.
However, they noted the links between cannabis potency and other mental health problems such as anxiety and depression were unclear.
Recent studies by the same team found the THC concentration in cannabis has increased significantly over time.
They said the findings, published in The Lancet Psychiatry, may help explain why more people have received treatment for cannabis problems over recent years, citing data from the European Monitoring Centre for Drugs and Drug Addiction which showed a 76% increase in people entering treatment for cannabis addiction in the past decade.
Based on the results, the authors argued for public health guidelines and policies to help make cannabis use safer.
Lead author Kat Petrilli said: “Our systematic review found that people who use higher-potency cannabis could be at increased risk of addiction, as well as psychosis, when compared to people who use cannabis products with lower potencies.
“These results are important in the context of harm reduction… it is important to acknowledge that a significant number of people across the world use cannabis regularly, and to ensure they can make informed decisions that could reduce any possible harms associated with it.”
The researchers said strategies to make cannabis use safer could inform how the drug is regulated around the world.
Senior author Dr Tom Freeman added: “In places where cannabis is legally sold, providing consumers with accurate information on product content and access to lower-potency products could help people to use cannabis more safely.”